You searched for subject:(magnetization).
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Montana State University
1.
Gilmore, Keith.
Precession damping in itinerant ferromagnets.
Degree: PhD, College of Letters & Science, 2007, Montana State University
URL: https://scholarworks.montana.edu/xmlui/handle/1/1336 
► The energy of the spin system changes by two mechanism: the energies of the states change and transitions to excited states occur. The first mechanism…
(more)
▼ The energy of the spin system changes by two mechanism: the energies of the states change and transitions to excited states occur. The first mechanism had previously been described within the effective field picture as producing a breathing of the Fermi surface. As the
magnetization precesses, the spin-orbit energy of each state changes leading to expansions and contractions of the Fermi surface that are periodic with the precession. To expand this metaphor, we have dubbed the second effect of transitions to excited states as a bubbling of the Fermi sea. In this picture, individual electrons across the Fermi surface undergo larger excitations. Finally, we investigated the dependence of the damping rate on the density of states and the spin-orbit coupling parameter. We found that the damping due to the breathing effect was roughly proportional to the density of states while damping from the bubbling terms correlated strongly with the density of states squared. By tuning the spin-orbit parameter we found that the breathing terms were proportional to the spin-orbit parameter cubed while the bubbling terms went as the spin-orbit parameter squared.
Advisors/Committee Members: Chairperson, Graduate Committee: Yves U. Idzerda, Mark Stiles (co-chair) (advisor).
Subjects/Keywords: Magnetization
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APA (6th Edition):
Gilmore, K. (2007). Precession damping in itinerant ferromagnets. (Doctoral Dissertation). Montana State University. Retrieved from https://scholarworks.montana.edu/xmlui/handle/1/1336
Chicago Manual of Style (16th Edition):
Gilmore, Keith. “Precession damping in itinerant ferromagnets.” 2007. Doctoral Dissertation, Montana State University. Accessed April 10, 2021.
https://scholarworks.montana.edu/xmlui/handle/1/1336.
MLA Handbook (7th Edition):
Gilmore, Keith. “Precession damping in itinerant ferromagnets.” 2007. Web. 10 Apr 2021.
Vancouver:
Gilmore K. Precession damping in itinerant ferromagnets. [Internet] [Doctoral dissertation]. Montana State University; 2007. [cited 2021 Apr 10].
Available from: https://scholarworks.montana.edu/xmlui/handle/1/1336.
Council of Science Editors:
Gilmore K. Precession damping in itinerant ferromagnets. [Doctoral Dissertation]. Montana State University; 2007. Available from: https://scholarworks.montana.edu/xmlui/handle/1/1336
Boston University
2.
Maier, Mihaela.
Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T.
Degree: MS, Bioimaging, 2017, Boston University
URL: http://hdl.handle.net/2144/26732
► PURPOSE: To assess the variability of incidental magnetization transfer effect (MT) by the number of slices and the magnetic field strength. METHODS: Various magnetic resonance…
(more)
▼ PURPOSE: To assess the variability of incidental magnetization transfer effect (MT) by the number of slices and the magnetic field strength.
METHODS: Various magnetic resonance images (MRI) were obtained with a phantom containing a series of solutions of gadolinium (Gd) and sucrose in distilled water, agarose gel and two vials with olive oil and distilled water. A diffusion weighted image (DWI) sequence was acquired to determine diffusion coefficient for each component of the phantom. Several inversion recovery (IR) sequences having different TI values were run for single-slice and used to calculate T1 relaxation time with maximum precision and minimizing magnetization transfer effect. The T1 relaxation value resulting from processing IR sequences was used as reference value. The mixed-TSE sequences were used to calculate T1, T2 and PD values and to assess MT effect for single-slice as for multi-slice acquisition. All the DICOM MR images were processed using various algorithms programmed in Mathcad (version 2001i, PTC Needham, MA) by Dr. Hernan Jara. According with the potential of each sequences the programs generated the qMRI maps and values of T1, T2, PD were obtained for all the components of the phantom. Values resulted from Mathcad calculation were used for analysis. All the acquisitions, calculations and measurements were performed for 1.5T and 3T field strength.
Subjects/Keywords: Medical imaging; Relaxometry; Magnetization transfer
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APA (6th Edition):
Maier, M. (2017). Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T. (Masters Thesis). Boston University. Retrieved from http://hdl.handle.net/2144/26732
Chicago Manual of Style (16th Edition):
Maier, Mihaela. “Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T.” 2017. Masters Thesis, Boston University. Accessed April 10, 2021.
http://hdl.handle.net/2144/26732.
MLA Handbook (7th Edition):
Maier, Mihaela. “Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T.” 2017. Web. 10 Apr 2021.
Vancouver:
Maier M. Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T. [Internet] [Masters thesis]. Boston University; 2017. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/2144/26732.
Council of Science Editors:
Maier M. Magnetization transfer effect on T1 relaxometry on 1.5T vs. 3T. [Masters Thesis]. Boston University; 2017. Available from: http://hdl.handle.net/2144/26732
University of Minnesota
3.
Molinek, Frank.
The magnetization and relative paleointensity of experimentally deposited natural sediments.
Degree: MS, Earth Sciences, 2017, University of Minnesota
URL: http://hdl.handle.net/11299/190589
► The magnetization of a sediment occurs when ferromagnetic detrital particles align with a depositional magnetic field. The geomagnetic field can be approximated by a dipole…
(more)
▼ The magnetization of a sediment occurs when ferromagnetic detrital particles align with a depositional magnetic field. The geomagnetic field can be approximated by a dipole that averages to share an axis with the rotation of the Earth. This field exerts a magnetic torque on ferromagnetic particles such as magnetite. However, processes including flocculation, contact with the substrate, bioturbation, and compaction disrupt this alignment, leading to shallowed remanent inclinations and biased intensities. The dependence of paleointensity on the inclination of the depositional field leads to complications in interpretations, despite the relative continuity and ubiquity of the global sedimentary record. We present a series of 12 deposition experiments in varying field strengths and inclinations, and attempt to correct relative paleointensity estimates using the anisotropy of anhysteretic remanence. We find experimentally that this correction reduces the inclination dependence of relative paleointensity, suggesting that it should also improve those estimates in naturally occurring sediments.
Subjects/Keywords: anisotropy; magnetization; paleointensity; sediments
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APA (6th Edition):
Molinek, F. (2017). The magnetization and relative paleointensity of experimentally deposited natural sediments. (Masters Thesis). University of Minnesota. Retrieved from http://hdl.handle.net/11299/190589
Chicago Manual of Style (16th Edition):
Molinek, Frank. “The magnetization and relative paleointensity of experimentally deposited natural sediments.” 2017. Masters Thesis, University of Minnesota. Accessed April 10, 2021.
http://hdl.handle.net/11299/190589.
MLA Handbook (7th Edition):
Molinek, Frank. “The magnetization and relative paleointensity of experimentally deposited natural sediments.” 2017. Web. 10 Apr 2021.
Vancouver:
Molinek F. The magnetization and relative paleointensity of experimentally deposited natural sediments. [Internet] [Masters thesis]. University of Minnesota; 2017. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/11299/190589.
Council of Science Editors:
Molinek F. The magnetization and relative paleointensity of experimentally deposited natural sediments. [Masters Thesis]. University of Minnesota; 2017. Available from: http://hdl.handle.net/11299/190589
Georgia Tech
4.
Copeland, John Alexander.
First order Green function theory of the Heisenberg ferromagnet.
Degree: PhD, Physics, 1965, Georgia Tech
URL: http://hdl.handle.net/1853/29346
Subjects/Keywords: Magnetization; Ferromagnetism
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APA (6th Edition):
Copeland, J. A. (1965). First order Green function theory of the Heisenberg ferromagnet. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29346
Chicago Manual of Style (16th Edition):
Copeland, John Alexander. “First order Green function theory of the Heisenberg ferromagnet.” 1965. Doctoral Dissertation, Georgia Tech. Accessed April 10, 2021.
http://hdl.handle.net/1853/29346.
MLA Handbook (7th Edition):
Copeland, John Alexander. “First order Green function theory of the Heisenberg ferromagnet.” 1965. Web. 10 Apr 2021.
Vancouver:
Copeland JA. First order Green function theory of the Heisenberg ferromagnet. [Internet] [Doctoral dissertation]. Georgia Tech; 1965. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1853/29346.
Council of Science Editors:
Copeland JA. First order Green function theory of the Heisenberg ferromagnet. [Doctoral Dissertation]. Georgia Tech; 1965. Available from: http://hdl.handle.net/1853/29346
Kansas State University
5.
Bornemeier, Dwight Daniel.
Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress.
Degree: 1960, Kansas State University
URL: http://hdl.handle.net/2097/18517
Subjects/Keywords: Magnetization; Ferromagnetism
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APA (6th Edition):
Bornemeier, D. D. (1960). Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress. (Thesis). Kansas State University. Retrieved from http://hdl.handle.net/2097/18517
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Bornemeier, Dwight Daniel. “Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress.” 1960. Thesis, Kansas State University. Accessed April 10, 2021.
http://hdl.handle.net/2097/18517.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Bornemeier, Dwight Daniel. “Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress.” 1960. Web. 10 Apr 2021.
Vancouver:
Bornemeier DD. Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress. [Internet] [Thesis]. Kansas State University; 1960. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/2097/18517.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Bornemeier DD. Determination of the longitudinal magnetization curves of polarized nickel-iron wires under torsional stress. [Thesis]. Kansas State University; 1960. Available from: http://hdl.handle.net/2097/18517
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
6.
Gunawardana, Hiruni.
Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON.
Degree: 2017, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/4946
► Drill core samples obtained from four mineralized zones of the Marathon Cu-PGE deposit in the Coldwell igneous complex have been investigated for their petrophysical characteristics.…
(more)
▼ Drill core samples obtained from four mineralized zones of the Marathon Cu-PGE deposit in the Coldwell igneous complex have been investigated for their petrophysical characteristics. Remanent magnetization was used as a possible tool to reorient core samples but a drilling induced overprint magnetization dominated the record. Anisotropy of magnetic susceptibility was measured to provide a proxy for the petrofabric of samples obtained from oriented drill cores; a well-defined planar fabric was found to strike 177 and dip 25°W, with down-dip lineation, in excellent agreement with inferred magmatic flow direction based on 3D modeling of mineralized footwall troughs. Magnetite rich lithologies of the deposit show anomalous magnetic susceptibilities, natural remanent magnetizations, chargeabilities and resistivities which can be used as a resource vectoring tool to guide geophysical surveys in defining new feeder channels and conduit systems. Acoustic impedance contrasts between lithological units and highly mineralized zones indicate the possibility of employing seismic methods (reflection, tomography) to investigate the subsurface distribution of mineralization.
Subjects/Keywords: induced magnetization; remanent magnetization; AMS; anisotropy; petrofabric; Geology; Geophysics and Seismology
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APA (6th Edition):
Gunawardana, H. (2017). Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/4946
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Gunawardana, Hiruni. “Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON.” 2017. Thesis, University of Western Ontario. Accessed April 10, 2021.
https://ir.lib.uwo.ca/etd/4946.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Gunawardana, Hiruni. “Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON.” 2017. Web. 10 Apr 2021.
Vancouver:
Gunawardana H. Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON. [Internet] [Thesis]. University of Western Ontario; 2017. [cited 2021 Apr 10].
Available from: https://ir.lib.uwo.ca/etd/4946.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Gunawardana H. Petrophysical Investigations of the Marathon Cu-PGE Deposit, Marathon, ON. [Thesis]. University of Western Ontario; 2017. Available from: https://ir.lib.uwo.ca/etd/4946
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Hong Kong University of Science and Technology
7.
Islam, Md Torikul PHYS.
Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient.
Degree: 2018, Hong Kong University of Science and Technology
URL: http://repository.ust.hk/ir/Record/1783.1-97830
;
https://doi.org/10.14711/thesis-991012662665703412
;
http://repository.ust.hk/ir/bitstream/1783.1-97830/1/th_redirect.html
► In this thesis, the magnetization manipulation has been investigated in two aspects, namely magnetization reversal of nanoparticle by microwave pulse & current and domain wall…
(more)
▼ In this thesis, the magnetization manipulation has been investigated in two aspects, namely magnetization reversal of nanoparticle by microwave pulse & current and domain wall (DW) dynamics along uniaxial nanowire under a thermal gradient. The magnetization reversal of high anisotropy magnetic nanoparticle (also known as Stoner particle) is studied by down-chirp pulse of circularly/linearly (CP/LP) polarized microwaves and spin polarized current simultaneously. Numerical results reveal that solely short down-chirp pulse of CP/LP microwave with certain range of initial frequency induces fast magnetization reversal. For this fast magnetization reversal, the underlying principle is the down-chirp microwave pulse maintains the phase difference with magnetization in such that the pulse acts as energy source and sink for magnetic particle before and after crossing the barrier respectively. Afterwards, the switching amplitude of chirped pulse is being reduced regarding practically realizable limit by applying a spin-polarized current additionally. This model and its findings might be helpful to realize fast magnetization switching of high anisotropy material with low current to achieve high thermal stability. Domain wall (DW) dynamics under the thermal gradient along uniaxial nanowire is investigated numerically. We use micromagnetic model in which the magnetization is governed by the stochastic Landau-Lifshitz- Gilbert equation. It is observed that DW always propagates towards hotter regions accompanying the rotation of DW plane (i.e., turbulent mode of DW propagation) around easy axis. DW rotation in uniaxial nanowire indicates the existence of breakdown limit. DW linear as well as angular velocity proportionately increases with the thermal gradient along the uniaxial nanowire. The spin/magnons current has been calculated and hence we estimate DW linear velocity. It is found the simulated DW velocity almost coincides with DW velocity which is calculated from magnon current density for small damping (~ 0.002). Moreover, DW velocity weakly depends on DW width (or uniaxial anisotropy), whereas DW angular velocity linearly increases with the decrease of the DW width (increase of uniaxial anisotropy). In the case of being damping dependent, DW linear and angular velocities decrease with damping constant, α. It is mentioned that all the features of DW dynamics under thermal gradient observed are analogous to that under electric STT, which justify the magnonic STT as underlying physics behind thermal gradient. Reasonably, by comparing the DW dynamics under a thermal gradient to that under electric STT, the coefficient of magnonic non-adiabatic STT, β is calculated. The magnitude of β does not depend on the thermal gradient. In addition, we observe that the β increases (decreases) with the uniaxial anisotropy Kx (damping α).
Subjects/Keywords: Magnetization
; Mathematical models
; Domain structure
; Electromagnetic interactions
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APA (6th Edition):
Islam, M. T. P. (2018). Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-97830 ; https://doi.org/10.14711/thesis-991012662665703412 ; http://repository.ust.hk/ir/bitstream/1783.1-97830/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Islam, Md Torikul PHYS. “Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient.” 2018. Thesis, Hong Kong University of Science and Technology. Accessed April 10, 2021.
http://repository.ust.hk/ir/Record/1783.1-97830 ; https://doi.org/10.14711/thesis-991012662665703412 ; http://repository.ust.hk/ir/bitstream/1783.1-97830/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Islam, Md Torikul PHYS. “Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient.” 2018. Web. 10 Apr 2021.
Vancouver:
Islam MTP. Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2018. [cited 2021 Apr 10].
Available from: http://repository.ust.hk/ir/Record/1783.1-97830 ; https://doi.org/10.14711/thesis-991012662665703412 ; http://repository.ust.hk/ir/bitstream/1783.1-97830/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Islam MTP. Magnetization reversal by field pulse & current and domain wall dynamics under thermal gradient. [Thesis]. Hong Kong University of Science and Technology; 2018. Available from: http://repository.ust.hk/ir/Record/1783.1-97830 ; https://doi.org/10.14711/thesis-991012662665703412 ; http://repository.ust.hk/ir/bitstream/1783.1-97830/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
8.
Bretzel, S.
Magneto-mechanical dynamics at the nanoscale.
Degree: 2011, Casimir Research School
URL: http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
;
urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
;
urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
;
http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
► Gyromagnetic experiments, the Barnett effect (magnetization by rotation) and the Einstein-de Haas effect (rotation by magnetization), were initially devised to test the molecular current hypothesis…
(more)
▼ Gyromagnetic experiments, the Barnett effect (
magnetization by rotation) and the Einstein-de Haas effect (rotation by
magnetization), were initially devised to test the molecular current hypothesis and determine the electron g-factor at the dawn of quantum mechanics. Advances in fabrication techniques and an ever increasing control of materials has led to continued miniaturization of not only integrated circuits but also of mechanical elements, such as cantilevers, giving rise to the field of micro-electro-mechanical devices (MEMS) and eventually nano-electro-mechanical devices (NEMS). In this thesis, we focused on the Barnett effect and the interplay of this effect with its close relative, the Einstein-de Haas effect in mesoscopic or nanoscopic systems. We perform a feasibility study concerning the Barnett effect in magnetic nanostructures and thin films. Furthermore, we study the the interplay of the Barnett and Einstein-de Haas effects in a suspended quasi one-dimensional magnetic wire containing a tail-to-tail domain wall and in a freely rotating grain containing a magnetic moment.
Advisors/Committee Members: Bauer, G.E.W..
Subjects/Keywords: NEMS; magnetization dynamics
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APA (6th Edition):
Bretzel, S. (2011). Magneto-mechanical dynamics at the nanoscale. (Doctoral Dissertation). Casimir Research School. Retrieved from http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
Chicago Manual of Style (16th Edition):
Bretzel, S. “Magneto-mechanical dynamics at the nanoscale.” 2011. Doctoral Dissertation, Casimir Research School. Accessed April 10, 2021.
http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb.
MLA Handbook (7th Edition):
Bretzel, S. “Magneto-mechanical dynamics at the nanoscale.” 2011. Web. 10 Apr 2021.
Vancouver:
Bretzel S. Magneto-mechanical dynamics at the nanoscale. [Internet] [Doctoral dissertation]. Casimir Research School; 2011. [cited 2021 Apr 10].
Available from: http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb.
Council of Science Editors:
Bretzel S. Magneto-mechanical dynamics at the nanoscale. [Doctoral Dissertation]. Casimir Research School; 2011. Available from: http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; urn:NBN:nl:ui:24-uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb ; http://resolver.tudelft.nl/uuid:0cc46fbb-f84d-41f4-804e-7080fdf8aedb
Delft University of Technology
9.
Vedula, Mano (author).
Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T.
Degree: 2020, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:ed118642-7370-471f-9045-948f656887e3
► Demyelination is described as loss of myelin sheath in neurons which could lead to disruption in signal transmission in nervous system. Inhomogeneous Magnetization Transfer(ihMT) is…
(more)
▼ Demyelination is described as loss of myelin sheath in neurons which could lead to disruption in signal transmission in nervous system. Inhomogeneous Magnetization Transfer(ihMT) is a novel MRI technique used to image myelin. It uses the dipolar coupling between methyl chains in lipid layers of myelin to acquire myelin specific information. In this study, we investigated the feasibility of ihMT at 7T. Based on phantom experiments and Bloch simulations, the influence of off-resonance frequency Δ, RF field strength B1 and RF pulse proprieties on ihMTR are studied and optimized. For in-vivo imaging, the experiments are conducted on healthy volunteers. Since B1 inhomogeneties are prevalent at higher fields, an optimized protocol is devised to achieve maximum ihMT effect at 7T. A comparison of 3T and 7T for the off-resonance frequency, RF field strength and pulse proprieties is presented to emphasize the impact of parameters at both the field strengths.
Electrical Engineering | Signals and Systems
Advisors/Committee Members: Remis, Rob (mentor), Ercan, Ece (graduation committee), Staring, Marius (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Myelin imaging; MRI; Inhomogeneous Magnetization Transfer
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APA (6th Edition):
Vedula, M. (. (2020). Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:ed118642-7370-471f-9045-948f656887e3
Chicago Manual of Style (16th Edition):
Vedula, Mano (author). “Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T.” 2020. Masters Thesis, Delft University of Technology. Accessed April 10, 2021.
http://resolver.tudelft.nl/uuid:ed118642-7370-471f-9045-948f656887e3.
MLA Handbook (7th Edition):
Vedula, Mano (author). “Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T.” 2020. Web. 10 Apr 2021.
Vancouver:
Vedula M(. Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Apr 10].
Available from: http://resolver.tudelft.nl/uuid:ed118642-7370-471f-9045-948f656887e3.
Council of Science Editors:
Vedula M(. Myelin Imaging in Brain using Inhomogeneous Magnetization Transfer(ihMT) at 3T and 7T. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:ed118642-7370-471f-9045-948f656887e3
University of Victoria
10.
Zhang, Lei.
Magnetization Damping in Microstructured Ferromagnetic Materials.
Degree: Dept. of Physics and Astronomy, 2013, University of Victoria
URL: http://hdl.handle.net/1828/4702
► The magnetization damping properties of square permalloy elements were characterized. These 20 nm-thick permalloy squares were deposited by the electron beam evaporation. Time resolved magneto-optic…
(more)
▼ The
magnetization damping properties of square permalloy elements were characterized. These 20 nm-thick permalloy squares were deposited by the electron beam evaporation. Time resolved magneto-optic Kerr effect microscopy (TR-MOKE) was used to measure the
magnetization evolution in the sample. By curve fitting in Matlab, I obtained the value of damping constant that is consistent with the reference paper.
A Landau confi guration in the square permalloy sample leads to the different trends of the damping constant with external bias field. The damping constant in the bottom domain is found to decrease with increasing bias field while the damping constant in the top domain has been saturated into the minimum value. The decreasing tendency of
magnetization precession frequencies is consistent with the Kittel equation modi fied with an anisotropic energy term.
Additionally, FePt thin films and patterned CoFeB disks were investigated but neither yielded conclusive dynamic data.
Advisors/Committee Members: Choi, Byoung-Chul (supervisor).
Subjects/Keywords: Magnetization Damping; Microstructured Ferromagnetic Materials; TR-MOKE
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APA (6th Edition):
Zhang, L. (2013). Magnetization Damping in Microstructured Ferromagnetic Materials. (Masters Thesis). University of Victoria. Retrieved from http://hdl.handle.net/1828/4702
Chicago Manual of Style (16th Edition):
Zhang, Lei. “Magnetization Damping in Microstructured Ferromagnetic Materials.” 2013. Masters Thesis, University of Victoria. Accessed April 10, 2021.
http://hdl.handle.net/1828/4702.
MLA Handbook (7th Edition):
Zhang, Lei. “Magnetization Damping in Microstructured Ferromagnetic Materials.” 2013. Web. 10 Apr 2021.
Vancouver:
Zhang L. Magnetization Damping in Microstructured Ferromagnetic Materials. [Internet] [Masters thesis]. University of Victoria; 2013. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1828/4702.
Council of Science Editors:
Zhang L. Magnetization Damping in Microstructured Ferromagnetic Materials. [Masters Thesis]. University of Victoria; 2013. Available from: http://hdl.handle.net/1828/4702
University of Missouri – Columbia
11.
He, Jiexuan, 1980-.
Effects of spin current in ferromagnets.
Degree: PhD, 2008, University of Missouri – Columbia
URL: http://hdl.handle.net/10355/6060
► [ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This thesis focuses on the investigation of magnetization dynamics induced by spin transfer torques.…
(more)
▼ [ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This thesis focuses on the investigation of
magnetization dynamics induced by spin transfer torques. The first part of this thesis presents the theoretical and numerical study of domain wall motion in the magnetic nanowire. The second part reports the analysis of spin-current-driven
magnetization excitations in ferromagnets. Magnetic domain wall is known as the transition region between magnetic domains whose
magnetization pointing in different directions. Via the movement of domain wall, these domains can rearrange themselves in response to the external magnetic field or electric current. Domain wall dynamics is an important issue in study of the dynamic behavior of magnetic systems. Transverse wall and vortex wall are two type of walls mostly observed in magnetic thin films. Analytical models for these two walls are proposed in this thesis, and their dynamic behaviors are studied by these models. Micromagnetic simulations are performed to verify our analytical results. Simulation results also reveal the physical origin of many phenomena observed in experiments. The direct interaction between conducting electrons and local moments polarizes the electron spins, and at the same time, exerts a spin torque on the
magnetization. When the current density is increased higher than a critical value, the spin torque is able to drive the magnetic system out of equilibrium. Due to the existence of the magnetic damping, a steady state could still be reached in this fluctuation-dissipation system. Physical properties of this dynamic state are studied and presented.
Advisors/Committee Members: Zhang, Shufeng, 1963- (advisor).
Subjects/Keywords: Magnetization; Spintronics; Ferromagnetism
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APA (6th Edition):
He, Jiexuan, 1. (2008). Effects of spin current in ferromagnets. (Doctoral Dissertation). University of Missouri – Columbia. Retrieved from http://hdl.handle.net/10355/6060
Chicago Manual of Style (16th Edition):
He, Jiexuan, 1980-. “Effects of spin current in ferromagnets.” 2008. Doctoral Dissertation, University of Missouri – Columbia. Accessed April 10, 2021.
http://hdl.handle.net/10355/6060.
MLA Handbook (7th Edition):
He, Jiexuan, 1980-. “Effects of spin current in ferromagnets.” 2008. Web. 10 Apr 2021.
Vancouver:
He, Jiexuan 1. Effects of spin current in ferromagnets. [Internet] [Doctoral dissertation]. University of Missouri – Columbia; 2008. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/10355/6060.
Council of Science Editors:
He, Jiexuan 1. Effects of spin current in ferromagnets. [Doctoral Dissertation]. University of Missouri – Columbia; 2008. Available from: http://hdl.handle.net/10355/6060
Louisiana State University
12.
Schurr, Ryan Nicholas.
Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla.
Degree: MS, Physical Sciences and Mathematics, 2015, Louisiana State University
URL: etd-06182015-155915
;
https://digitalcommons.lsu.edu/gradschool_theses/2661
► Chemical exchange saturation transfer (CEST) and magnetization transfer (MT) are types of magnetic resonance imaging (MRI) experiments in which contrast is based on the transfer…
(more)
▼ Chemical exchange saturation transfer (CEST) and magnetization transfer (MT) are types of magnetic resonance imaging (MRI) experiments in which contrast is based on the transfer of magnetization from selectively saturated solute or macromolecular protons to bulk water protons. These processes offer insight into the chemical composition of tissue and are quantified by the asymmetry of the magnetization transfer ratio (MTRasym). This study was to develop a Z-spectral curve fitting procedure based on the underlying physics of CEST-MRI from which MTRasym values can be calculated and applied to distinguish healthy tissue from cancer. Z-spectra were collected from CEST-MR images of a phantom. The data were fit to both the proposed model which separately fits the upfield and downfield regions of the Z-spectra, and two polynomial models from literature. A preferred model was identified using the small sample bias-corrected Akaike’s Information Criterion (AICc). Z-spectra were collected from CEST-MR images of prostate cancer patients and fit with the same models; the preferred model was selected using the AICc. CEST-MR images of bladder cancer patients were acquired and the Z-spectra were fit with the preferred model identified from the phantom images. MTRasym was calculated at frequency offsets of 3.5 ppm and 2.0 ppm to determine if these quantities were capable of distinguishing normal bladder wall (NBW) from bladder cancer. The proposed fitting model with a 5th order polynomial for the downfield region was the preferred curve fitting model by the AICc model selection procedure for the phantom while a 6th order polynomial was preferred for the prostate cancer Z-spectra. MTRasym(2.0 ppm) values calculated from the bladder cancer Z-spectra did not differ significantly between the NBW and tumor regions. A statistically significant difference existed between the NBW and tumor regions for the MTRasym(3.5 ppm) values (p < 0.001). The proposed model was preferred to the polynomial models from literature based on the AICc metric. Application of the technique to patient images showed the potential to distinguish NBW from bladder cancer based on the statistically significant MTRasym(3.5 ppm) values in these regions.
Subjects/Keywords: MRI; CEST; magnetization transfer; quantitative imaging
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APA (6th Edition):
Schurr, R. N. (2015). Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla. (Masters Thesis). Louisiana State University. Retrieved from etd-06182015-155915 ; https://digitalcommons.lsu.edu/gradschool_theses/2661
Chicago Manual of Style (16th Edition):
Schurr, Ryan Nicholas. “Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla.” 2015. Masters Thesis, Louisiana State University. Accessed April 10, 2021.
etd-06182015-155915 ; https://digitalcommons.lsu.edu/gradschool_theses/2661.
MLA Handbook (7th Edition):
Schurr, Ryan Nicholas. “Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla.” 2015. Web. 10 Apr 2021.
Vancouver:
Schurr RN. Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla. [Internet] [Masters thesis]. Louisiana State University; 2015. [cited 2021 Apr 10].
Available from: etd-06182015-155915 ; https://digitalcommons.lsu.edu/gradschool_theses/2661.
Council of Science Editors:
Schurr RN. Z-Spectral Modeling for Magnetization Transfer Ratio Asymmetry Calculations in Chemical Exchange Saturation Transfer MRI at 3 Tesla. [Masters Thesis]. Louisiana State University; 2015. Available from: etd-06182015-155915 ; https://digitalcommons.lsu.edu/gradschool_theses/2661
Colorado State University
13.
Swyt, Mitchell.
Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films.
Degree: MS(M.S.), Physics, 2020, Colorado State University
URL: http://hdl.handle.net/10217/219562
► This thesis focuses on the growth and characterization of ultra-low damping Co25Fe75 thin films. Ultra-low damping in a metal is of interest for the design…
(more)
▼ This thesis focuses on the growth and characterization of ultra-low damping Co25Fe75 thin films. Ultra-low damping in a metal is of interest for the design of new spintronic devices because this offers the opportunity to move both electrons and spin waves over appreciable distances. In this work, the effects of seed and capping layers on the damping parameter and
magnetization are investigated. A series of thin films were deposited using DC magnetron sputtering. A combination of X-ray reflectometry (XRR), vibrating sample magnetometry (VSM), and ferromagnetic resonance spectroscopy (FMR) were used to determine the film quality, saturation
magnetization, and damping parameters of each film. The results show that the Ta seed layers promoted smooth film growth for Co25Fe75, but direct interfaces with Ta or Pt resulting in enhanced damping. Cu spacer layers can be used to disrupt the enhancement but promote rough film growth for the studied sample growth conditions. Damping values in agreement with published results were achieved for two films from the set, with α=0.0064 ± 0.0004 for Ta/Co25Fe75 and α=0.0063 ± 0.0011 for Ta/Cu/Co25Fe75/Cu/Ta.
Advisors/Committee Members: Buchanan, Kristen (advisor), Ross, Kate (committee member), Menoni, Carmen (committee member).
Subjects/Keywords: magnetization dynamics; ultra-low damping; magnetometry; Co25Fe75
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APA (6th Edition):
Swyt, M. (2020). Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/219562
Chicago Manual of Style (16th Edition):
Swyt, Mitchell. “Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films.” 2020. Masters Thesis, Colorado State University. Accessed April 10, 2021.
http://hdl.handle.net/10217/219562.
MLA Handbook (7th Edition):
Swyt, Mitchell. “Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films.” 2020. Web. 10 Apr 2021.
Vancouver:
Swyt M. Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/10217/219562.
Council of Science Editors:
Swyt M. Growth and characterization of ultra-low damping Co₂₅Fe₇₅ thin films. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/219562
King Abdullah University of Science and Technology
14.
Li, Hang.
Spin Orbit Torque in Ferromagnetic Semiconductors.
Degree: Physical Science and Engineering (PSE) Division, 2016, King Abdullah University of Science and Technology
URL: http://hdl.handle.net/10754/614071
► Electrons not only have charges but also have spin. By utilizing the electron spin, the energy consumption of electronic devices can be reduced, their size…
(more)
▼ Electrons not only have charges but also have spin. By utilizing the electron spin, the energy consumption of electronic devices can be reduced, their size can be scaled down and the efficiency of `read' and `write' in memory devices can be significantly improved. Hence, the manipulation of electron spin in electronic devices becomes more and more appealing for the advancement of microelectronics. In spin-based devices, the manipulation of ferromagnetic order parameter using electrical currents is a very useful means for current-driven operation. Nowadays, most of magnetic memory devices are based on the so-called spin transfer torque, which stems from the spin angular momentum transfer between a spin-polarized current and the magnetic order parameter. Recently, a novel spin torque effect, exploiting spin-orbit coupling in non-centrosymmetric magnets, has attracted a massive amount of attention. This thesis addresses the nature of spin-orbit coupled transport and torques in non-centrosymmetric magnetic semiconductors.
We start with the theoretical study of spin orbit torque in three dimensional ferromagnetic GaMnAs. Using the Kubo formula, we calculate both the current-driven field-like torque and anti-damping-like torque. We compare the numerical results with the analytical expressions in the model case of a magnetic Rashba two-dimensional electron gas. Parametric dependencies of the different torque components and similarities to the analytical results of the Rashba two-dimensional electron gas in the weak disorder limit are described. Subsequently we study spin-orbit torques in two dimensional hexagonal crystals such as graphene, silicene, germanene and stanene. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom.
This thesis then addresses the influence of the quantum spin Hall effect on spin orbit torque in nanoribbons with a hexagonal lattice. We find a dramatic modification of the nature of the torque (field like and damping-like component) when crossing the topological phase transition. The relative agnitude of the two torque components can be significantly modifies by changing the
magnetization direction.
Finally, motivated by recent experimental results, we conclude by investigating the features of spin-orbit torque in magnetic transition metal dichalcogenides. We find the torque is associated with the valley polarization. By changing the
magnetization direction, the torque can be changed from a finite value to zero when the valley polarization decreases from a finite value to zero.
Advisors/Committee Members: Manchon, Aurelien (advisor), Schwingenschlögl, Udo (committee member), Li, Xiaohang (committee member), Duine, Rembert A. (committee member).
Subjects/Keywords: Spin Orbit Torque; Spin Orbit Coupling; Magnetization
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APA (6th Edition):
Li, H. (2016). Spin Orbit Torque in Ferromagnetic Semiconductors. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/614071
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Li, Hang. “Spin Orbit Torque in Ferromagnetic Semiconductors.” 2016. Thesis, King Abdullah University of Science and Technology. Accessed April 10, 2021.
http://hdl.handle.net/10754/614071.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Li, Hang. “Spin Orbit Torque in Ferromagnetic Semiconductors.” 2016. Web. 10 Apr 2021.
Vancouver:
Li H. Spin Orbit Torque in Ferromagnetic Semiconductors. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2016. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/10754/614071.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Li H. Spin Orbit Torque in Ferromagnetic Semiconductors. [Thesis]. King Abdullah University of Science and Technology; 2016. Available from: http://hdl.handle.net/10754/614071
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Victoria
15.
Xu, Haitian.
Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements.
Degree: Dept. of Physics and Astronomy, 2012, University of Victoria
URL: http://hdl.handle.net/1828/4173
► The magnetic properties and crystal texture of micron-sized, lithographically patterned ferromagnetic/antiferromagnetic (FM/AF) exchange-coupled elements supporting vortex remanent magnetization states were characterized using experimental and numerical…
(more)
▼ The magnetic properties and crystal texture of micron-sized, lithographically patterned ferromagnetic/antiferromagnetic (FM/AF) exchange-coupled elements supporting vortex remanent
magnetization states were characterized using experimental and numerical modeling techniques. 10umx10um square elements consisting of Ni80Fe20/Ir20Mn80 bilayers prepared on silicon and glass substrates using e-beam lithography and magnetron sputtering were thermomagnetically annealed under various in-plane cooling fields to induce exchange bias. Longitudinal and time-resolved Kerr effect microscopy were employed to measure the quasi-static hysteresis and dynamic response, while X-ray diffraction analysis was used to probe their crystal texture under different deposition and substrate conditions. The FM layer was found to be critical for the development of the necessary texture and spin alignment in the AF for creating interfacial exchange-bias. The exchange-bias field was found to significantly alter the magnetic behavior of the samples, leading to the stabilization of the vortex structure and asymmetric hysteresis loop shift in the quasi-static regime, as well as precessional frequency reduction of the bottom domain in the dynamic regime. Numerical simulations showed good qualitative agreement with both experimental observations and existing literature, and revealed the origin of the precessional frequency reduction as the different spin-wave eigenmodes excited by different remanent
magnetization states.
Advisors/Committee Members: Choi, Byoung-Chul (supervisor).
Subjects/Keywords: Exchange-bias; Magnetization dynamics; Vortex magnetization; Time-resolved magnetic microscopy; Numerical modeling
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APA (6th Edition):
Xu, H. (2012). Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements. (Masters Thesis). University of Victoria. Retrieved from http://hdl.handle.net/1828/4173
Chicago Manual of Style (16th Edition):
Xu, Haitian. “Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements.” 2012. Masters Thesis, University of Victoria. Accessed April 10, 2021.
http://hdl.handle.net/1828/4173.
MLA Handbook (7th Edition):
Xu, Haitian. “Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements.” 2012. Web. 10 Apr 2021.
Vancouver:
Xu H. Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements. [Internet] [Masters thesis]. University of Victoria; 2012. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1828/4173.
Council of Science Editors:
Xu H. Magnetization dynamics in lithographically patterned Ni80Fe20/Ir20Mn80 exchange-biased square elements. [Masters Thesis]. University of Victoria; 2012. Available from: http://hdl.handle.net/1828/4173
16.
Dupont, Louis.
Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets.
Degree: Docteur es, Chimie, 2018, Normandie
URL: http://www.theses.fr/2018NORMC209
► Les cryo-aimants supraconducteurs sont des sources de champs magnétiques intenses, compactes et peu gourmandes en énergie. Il existe diverses méthodes d’aimantation mais seule l’aimantation par…
(more)
▼ Les cryo-aimants supraconducteurs sont des sources de champs magnétiques intenses, compactes et peu gourmandes en énergie. Il existe diverses méthodes d’aimantation mais seule l’aimantation par champ magnétique pulsé (PFM) permet d’obtenir des champs excitateurs élevés sans recourir à des bobines supraconductrices refroidies.Basé sur une collaboration industrielle, ce travail a été consacré dans un premier temps à la conception d’un générateur de courant pulsé compact et évolutif générant des rampes de pulse de polarité réglage pouvant atteindre 3000A.Dans un second temps, nous avons mis en place les différents systèmes permettant l’aimantation des cryo-aimants refroidis soit à 77 K, soit dans un cryostat refroidi par un cryo-générateur.Enfin, l’aimantation par pulses de champ des cryo-aimants supraconducteurs a montré la possibilité de piéger un champ magnétique de l’ordre du tesla, réversible et reproductible. Les résultats obtenus répondent aux impératifs industriels de l’étude. Ils sont très encourageants pour le développement d’un dispositif de champ magnétique réversible à base de cryo-aimants supraconducteurs pour l’instrumentation scientifique ou pour les applications électrotechniques.
Superconducting cryomagnets are high magnetic fields sources that are both compact and energy efficient. There are various magnetization technics but only the magnetization by pulsed magnetic field (PFM) results in high excitation fields, that otherwise could only be obtained with large superconducting coils.This work was done in the framework of an industrial collaboration. In a first step, a compact and innovative pulse current generator enabling the generation of pulses with a 3000 Amps maximum intensity was designed and fabricated. Secondly, different systems for the magnetization of cryo-magnets either cooled down to 77 K or cooled in a cryostat by a cryo-generator were implemented. Finally, the pulsed field magnetization of superconducting cryo-magnets has shown that reversible and reproducible magnetic field in the one Tesla range could be generated by the set up.The results obtained are consistent with the industrial goals of this study. They are very encouraging for the development of reversible magnetic field devices based on superconducting cryo-magnets and dedicated to scientific instrumentation or for electrotechnical applications.
Advisors/Committee Members: Bernstein, Pierre (thesis director), Noudem, Jacques Guillaume (thesis director).
Subjects/Keywords: Cryo-aimants supraconducteurs; Générateur compact; Champ magnétique pulsé (PFM); Superconductor cryomagnets; Compact generator; Magnetization; Pulsed Field Magnetization (PFM)
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APA (6th Edition):
Dupont, L. (2018). Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets. (Doctoral Dissertation). Normandie. Retrieved from http://www.theses.fr/2018NORMC209
Chicago Manual of Style (16th Edition):
Dupont, Louis. “Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets.” 2018. Doctoral Dissertation, Normandie. Accessed April 10, 2021.
http://www.theses.fr/2018NORMC209.
MLA Handbook (7th Edition):
Dupont, Louis. “Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets.” 2018. Web. 10 Apr 2021.
Vancouver:
Dupont L. Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets. [Internet] [Doctoral dissertation]. Normandie; 2018. [cited 2021 Apr 10].
Available from: http://www.theses.fr/2018NORMC209.
Council of Science Editors:
Dupont L. Développement d'un dispositif de champ magnétique réversible à base des cryo-aimants supraconducteurs : Development of a pulsed magnetic field generator based on superconducting cryo-magnets. [Doctoral Dissertation]. Normandie; 2018. Available from: http://www.theses.fr/2018NORMC209
Université de Lorraine
17.
Gony, Bashar.
Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks.
Degree: Docteur es, Génie électrique, 2015, Université de Lorraine
URL: http://www.theses.fr/2015LORR0110
► Les pastilles supraconductrices peuvent produire des forts champs magnétiques très supérieurs aux aimants permanents. Plusieurs méthodes d’aimantation de ces pastilles existent néanmoins une seule est…
(more)
▼ Les pastilles supraconductrices peuvent produire des forts champs magnétiques très supérieurs aux aimants permanents. Plusieurs méthodes d’aimantation de ces pastilles existent néanmoins une seule est principalement utilisée pour les applications en génie électrique, l’aimantation par champ magnétique impulsionnel (Pulsed Field Magnetization). Afin de maîtriser l’aimantation de ces pastilles supraconductrices par PFM, nous avons étudié l’influence de la forme de l’inducteur sur le champ magnétique piégé où nous trouvons une influence significative de la forme de l’inducteur sur le champ piégé dans la pastille supraconductrice. Afin de prévoir la mise en oeuvre des pastilles supraconductrices dans des applications en génie électrique, nous avons étudié l’aimantation de ces pastilles dans un circuit magnétique et l’influence de ce circuit sur le champ piégé. Nous remarquons une nette amélioration du champ piégé dans la pastille en utilisant le circuit magnétique. Nous avons étudié, également, l’influence d’un champ démagnétisant impulsionnel et alternatif sur le champ piégé dans une pastille supraconductrice aimantée. Les dégradations observées ne montrent pas de contre-indication à l’utilisation des pastilles supraconductrices aimantées dans les applications en génie électrique.
The superconducting bulks can produce very strong magnetic fields greater than those of permanent magnets can. Several methods of magnetization of the superconducting bulks exist, however one is mainly used for the electrical applications, the Pulsed Field Magnetization. In order to control the magnetization of the superconducting bulks by PFM, we studied the influence of the shape of the inductor on the trapped magnetic field where we find a significant influence of the shape of the inductor on the trapped magnetic field in the anticipate superconducting bulk. In order to the implementation of the superconducting bulk in the electrical applications, we studied the magnetization of these bulks in a magnetic core and the influence of this magnetic core on the trapped magnetic field. We notice an important improvement of the trapped magnetic field in the superconducting bulk by using the magnetic core. We studied also the influence of a pulsed and an alternating demagnetizing field on the trapped magnetic field in a superconducting bulk. The observed degradation does not show any contraindication to use the superconducting magnetic bulks in the electrical engineering applications.
Advisors/Committee Members: Douine, Bruno (thesis director), Berger, Kévin (thesis director).
Subjects/Keywords: Supraconducteur; Aimantation; Champs impulsionnels; Modélisation; Superconductor; Magnetization; Pulsed Field Magnetization (PFM); Modelling; 539.725; 538.4; 620.112 973
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APA (6th Edition):
Gony, B. (2015). Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks. (Doctoral Dissertation). Université de Lorraine. Retrieved from http://www.theses.fr/2015LORR0110
Chicago Manual of Style (16th Edition):
Gony, Bashar. “Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks.” 2015. Doctoral Dissertation, Université de Lorraine. Accessed April 10, 2021.
http://www.theses.fr/2015LORR0110.
MLA Handbook (7th Edition):
Gony, Bashar. “Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks.” 2015. Web. 10 Apr 2021.
Vancouver:
Gony B. Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks. [Internet] [Doctoral dissertation]. Université de Lorraine; 2015. [cited 2021 Apr 10].
Available from: http://www.theses.fr/2015LORR0110.
Council of Science Editors:
Gony B. Aimantation de pastilles supraconductrices : Magnetization of superconducting bulks. [Doctoral Dissertation]. Université de Lorraine; 2015. Available from: http://www.theses.fr/2015LORR0110
University of Edinburgh
18.
Turner, Gillian M.
Geomagnetic investigations of some recent British sediments.
Degree: PhD, 1980, University of Edinburgh
URL: http://hdl.handle.net/1842/36131
► In order to study the geomagnetic secular variation in Britain during the past 10000 years six metre and one metre long cores of post -Glacial…
(more)
▼ In order to study the geomagnetic secular variation in Britain during the past 10000 years six metre and one metre long cores of post -Glacial sediment have been collected from three British lakes. Magnetic measurements were made on both the whole cores and on sub - samples from them. The natural remanent magnetization is stable, and records well defined declination and inclination swings of 40 -50° and 15 -20° peak-peak amplitudes respectively. There is also much between swing detail. Both the major swings and many finer details are readily correlated from core to core and lake to lake. Thirty radiocarbon age determinations, pollen analyses and correlations with observatory and archaeomagnetic records have been combined to derive a detailed time scale. This time scale has been transferred to all the ' cores by means of magnetic susceptibility and lithological correlations. Fourier analyses of declination and inclination, separately and combined as a complex pair, show that the variations are not simply periodic, nor is their spectrum constant with time. The geomagnetic vector has been looping in a clockwise sense for most of the past 10000 years. The records have been compared with other lacustrine and archaeomagnetic results from other countries, and various models for the non dipole field are discussed in the light of all these records. Attempts to retrieve palaeointensities from the sediments have shown that ARM may provide an effective normalization parameter in some, but by no means all cases. Determining the suitability of sediments for palaeointensity, studies is complicated. Field tests were carried out to investigate the magnetic minerals in the soils of the drainage basin of one lake; soil and lake sediment samples were further analysed in the laboratory. In addition to magnetite an impure form of maghaemite appears to play some part in carrying the NRM of this lake sediment. Continental shelf sediment cores have also been collected from the Firth of Clyde. These have been correlated with each other by their susceptibility logs, and dated by correlation of their secular variation records with the lake sediment record.
Subjects/Keywords: 551.7; geomagnetic field; Palaeomagnetism; Thermoremanent magnetization; Detrital remanent magnetization
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APA (6th Edition):
Turner, G. M. (1980). Geomagnetic investigations of some recent British sediments. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/36131
Chicago Manual of Style (16th Edition):
Turner, Gillian M. “Geomagnetic investigations of some recent British sediments.” 1980. Doctoral Dissertation, University of Edinburgh. Accessed April 10, 2021.
http://hdl.handle.net/1842/36131.
MLA Handbook (7th Edition):
Turner, Gillian M. “Geomagnetic investigations of some recent British sediments.” 1980. Web. 10 Apr 2021.
Vancouver:
Turner GM. Geomagnetic investigations of some recent British sediments. [Internet] [Doctoral dissertation]. University of Edinburgh; 1980. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1842/36131.
Council of Science Editors:
Turner GM. Geomagnetic investigations of some recent British sediments. [Doctoral Dissertation]. University of Edinburgh; 1980. Available from: http://hdl.handle.net/1842/36131
Universiteit Utrecht
19.
Oorschot, J.W.M. van.
Endogenous assessment of myocardial fibrosis with quantitative MRI.
Degree: 2016, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/328798
► In this thesis, we have studied the use of quantitative MR contrast mechanisms, that could potentially be used for endogenous detection of myocardial fibrosis in…
(more)
▼ In this thesis, we have studied the use of quantitative MR contrast mechanisms, that could potentially be used for endogenous detection of myocardial fibrosis in the clinic. we have mainly focused on T2*, T1ρ MRI and
Magnetization Transfer Imaging, and found that T1ρ -mapping, and
Magnetization Transfer imaging are most promising. We found a significantly higher T1ρ-relaxation time in myocardial infarct tissue, compared to healthy remote tissue, both in a porcine animal model and chronic infarct patients. A comparison with LGE as gold standard for infarct detection, showed that native T1ρ –maps can be used to locate the myocardial scar area. For diffuse myocardial fibrosis, we have shown that T1ρ relaxation times correlate with the amount of fibrosis, determined by histology, and with extracellular volume fraction, measured in vivo. The results of native T1 –mapping in DCM patients did not indicate a significant relation with extracellular volume fraction in patients. Measurements of
magnetization transfer in an animal model showed a decrease in
magnetization transfer ratio in the infarct area, and the addition of an MT pulse in front of a T1ρ-mapping experiment resulted in a significantly higher T1ρ-relaxation time.
For infarct detection with T1ρ –mapping the main advantage compared to gold standard LGE imaging is that a contrast agent is no longer required. As a first step towards clinical applications, this technique could be used as an alternative in patients that are unable to receive a gadolinium based contrast agent, such as patients with severe renal failure. Also for diffuse fibrosis, T1ρ –mapping can be used as an alternative to the gadolinium based ECV-mapping. When the sensitivity of the technique is significantly increased, it could be considered as an alternative for LGE and ECV-mapping in clinical practice for all patients.
Advisors/Committee Members: Luijten, P.R., Leiner, T., Zwanenburg, J.J.M..
Subjects/Keywords: MRI; Cardiac; Heart; Endogenous; T1rho; Magnetization Transfer; Contrast agent; Native
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APA (6th Edition):
Oorschot, J. W. M. v. (2016). Endogenous assessment of myocardial fibrosis with quantitative MRI. (Doctoral Dissertation). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/328798
Chicago Manual of Style (16th Edition):
Oorschot, J W M van. “Endogenous assessment of myocardial fibrosis with quantitative MRI.” 2016. Doctoral Dissertation, Universiteit Utrecht. Accessed April 10, 2021.
http://dspace.library.uu.nl:8080/handle/1874/328798.
MLA Handbook (7th Edition):
Oorschot, J W M van. “Endogenous assessment of myocardial fibrosis with quantitative MRI.” 2016. Web. 10 Apr 2021.
Vancouver:
Oorschot JWMv. Endogenous assessment of myocardial fibrosis with quantitative MRI. [Internet] [Doctoral dissertation]. Universiteit Utrecht; 2016. [cited 2021 Apr 10].
Available from: http://dspace.library.uu.nl:8080/handle/1874/328798.
Council of Science Editors:
Oorschot JWMv. Endogenous assessment of myocardial fibrosis with quantitative MRI. [Doctoral Dissertation]. Universiteit Utrecht; 2016. Available from: http://dspace.library.uu.nl:8080/handle/1874/328798
Mississippi State University
20.
Dixit, Vivek.
First principles investigation of substituted strontium hexaferrite.
Degree: PhD, Physics and Astronomy, 2015, Mississippi State University
URL: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10202015-121304/
;
► This dissertation investigates how the magnetic properties of strontium hexaferrite change upon the substitution of foreign atoms at the Fe sites. Strontium hexaferrite, SrFe12O19…
(more)
▼ This dissertation investigates how the magnetic properties of strontium hexaferrite
change upon the substitution of foreign atoms at the Fe sites. Strontium hexaferrite,
SrFe
12O
19 is a commonly used hard magnetic material and is produced in large quantities
(around 500,000 tons per year). For different applications of strontium hexaferrite, its
magnetic properties can be tuned by a proper substitution of the foreign atoms. Experimental
screening for a proper substitution is a cost-intensive and time-consuming process,
whereas computationally it can be done more efficiently. We used the density functional
theory a first principles based method to study substituted strontium hexaferrite. The site
occupancies of the substituted atoms were estimated by calculating the substitution energies
of different configurations. The formation probabilities of configurations were used to
calculate the magnetic properties of substituted strontium hexaferrite.
In the first study, Al-substituted strontium hexaferrite, SrFe<sub>12-<i>x</i></sub>Al<sub> <i>x</i> </sub>O
19, with <i>x</i> = 0.5
and <i>x</i> = 1.0 were investigated. It was found that at the annealing temperature the nonmagnetic
Al
+3 ions preferentially replace Fe
+3 ions from the 12<i>k</i> and 2<i>a</i> sites. We found
that the
magnetization decreases and the magnetic anisotropy field increases as the fraction,
<i>x</i> of the Al atoms increases.
In the second study, SrFe<sub>12-<i>x</i> </sub>Ga<sub><i>x</i></sub> O
19 and SrFe<sub>12-<i>x</i></sub> In<sub><i>x</i></sub> O
19 with <i>x</i> = 0.5 and <i>x</i> = 1.0
were investigated. In the case of SrFe<sub>12-<i>x</i></sub> Ga<sub><i>x</i></sub> O
19, the sites where Ga
+3 ions prefer to
enter are: 12<i>k</i>, 2<i>a</i>, and 4<i>f
1</i>. For SrFe<sub>12-<i>x</i></sub> In<sub><i>x</i></sub> O
19, In
+3 ions most likely to occupy the
12<i>k</i>, 4<i>f
1</i>, and 4<i>f
2</i> sites. In both cases the
magnetization was found to decrease slightly
as the fraction of substituted atom increases. The magnetic anisotropy field increased for
SrFe<sub>12-<i>x</i></sub> Ga<sub><i>x</i></sub> O
19, and decreased for SrFe<sub>12-<i>x</i></sub> In<sub><i>x</i> </sub>O
19 as the concentration of substituted
atoms increased.
In the third study, 23 elements (M) were screened for their possible substitution in
strontium hexaferrite, SrFe<sub>12-<i>x</i></sub> M<sub><i>x</i> </sub>O
19 with <i>x</i> = 0.5. In each case the site preference of the
substituted atom and the magnetic properties were calculated. We found that Bi, Ge, Sb,
Sn, and Sc can effectively increase the
magnetization, and Cr, P, Co, Al, Ga, and Ti can
increase the anisotropy field when substituted into strontium hexaferrite.
Advisors/Committee Members: Seong-Gon Kim (chair), Mark F. Horstemeyer (committee member), Mark A. Novotny (committee member), Steven R. Gwaltney (committee member), R. Torsten Clay (committee member).
Subjects/Keywords: Substitution; Strontium Hexaferrite; Density Functional Theory; Site Preference; Magnetization; Magnetic Anisotropy.
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APA (6th Edition):
Dixit, V. (2015). First principles investigation of substituted strontium hexaferrite. (Doctoral Dissertation). Mississippi State University. Retrieved from http://sun.library.msstate.edu/ETD-db/theses/available/etd-10202015-121304/ ;
Chicago Manual of Style (16th Edition):
Dixit, Vivek. “First principles investigation of substituted strontium hexaferrite.” 2015. Doctoral Dissertation, Mississippi State University. Accessed April 10, 2021.
http://sun.library.msstate.edu/ETD-db/theses/available/etd-10202015-121304/ ;.
MLA Handbook (7th Edition):
Dixit, Vivek. “First principles investigation of substituted strontium hexaferrite.” 2015. Web. 10 Apr 2021.
Vancouver:
Dixit V. First principles investigation of substituted strontium hexaferrite. [Internet] [Doctoral dissertation]. Mississippi State University; 2015. [cited 2021 Apr 10].
Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10202015-121304/ ;.
Council of Science Editors:
Dixit V. First principles investigation of substituted strontium hexaferrite. [Doctoral Dissertation]. Mississippi State University; 2015. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10202015-121304/ ;
University of Missouri – Kansas City
21.
Charlapally, Akhila.
Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization.
Degree: 2017, University of Missouri – Kansas City
URL: http://hdl.handle.net/10355/61852
► Energization of large power transformers are subject to many transients that may complicate the successful completion of this process and ultimately reduce the expected life…
(more)
▼ Energization of large power transformers are
subject to many transients that may
complicate the successful completion of this process and ultimately reduce the expected life
of these critical components. The first-time energization (commissioning), subsequent
energizations (operational), methods of energization (abrupt or controlled energizations
from the high voltage or low voltage winding) and the possibility/improbability of these
transformers being preloaded all affect the transformer’s longevity. The consequences of
such energizations during the conditions are inrush currents and voltage stresses on the
affected components that may not be foremost on the designer’s mind. The designer may be
more concerned with proper parameter application and not the effects of commissioning and
operation on these massive components. These behemoths are a bit akin to elephants whose
longevity is dependent on the sum of their life experiences and the scars they endure during
this period. The reliability of electric system is directly affected by these series connected
behemoths.
The construction of power transformers has been optimized by the advent of
computers (especially finite analyses) to the point that stray flux, eddy current, hysteresis
loss and harmonic loss (embodied and represented within the non-linear Rₚ element and
known as “core Watt losses”) have all attained significant improvements witnessed by their
99.8+ percent efficiency. The difficulties that remain are magnetizing inrush and remanence
embodied within Xₚ which occur dependent on three parameters. The parameters are
primary resistance Rₛ (dependent on the location of same for the equivalent circuit used), the
time dependent voltage at the point on the voltage wave when the transformer is energized
(referred to as “Point of Wave”) and the remanent (or residual flux) and its polarity all at the
instant of energization.
The magnetizing inrush problem has been thoroughly researched and commercial
products exist to mitigate such difficulties by control system add-ons. This research
recognizes that knowledge of Point on Wave has effectively mitigated the problems with
transformer energization at zero voltage.
The results obtained after hundreds of runs confirms a direct relationship between
the point of the wave where current is extinguished for a fast acting air switch and minimal
to zero remanence flux in a single-phase shell form transformer. This minimal to zero
residual flux appears at the peak of the equivalent sinusoidal current wave (increasing or
decreasing) without the effects of saturation.
The conclusion of the experimental runs was that the use of multiple Hall-Effect
transducers (multiple installations suggested for manufacturing errors or wiring failures)
within the laminations of a transformer which would be used to confirm the near zero
remanent flux once the current was extinguished as described above. These findings and
recommendations are still
subject to testing at…
Advisors/Committee Members: Goli, Preetham (advisor).
Subjects/Keywords: Electric transformers; Magnetization; Thesis – University of Missouri – Kansas City – Engineering
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APA ·
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CSE |
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APA (6th Edition):
Charlapally, A. (2017). Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization. (Thesis). University of Missouri – Kansas City. Retrieved from http://hdl.handle.net/10355/61852
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Charlapally, Akhila. “Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization.” 2017. Thesis, University of Missouri – Kansas City. Accessed April 10, 2021.
http://hdl.handle.net/10355/61852.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Charlapally, Akhila. “Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization.” 2017. Web. 10 Apr 2021.
Vancouver:
Charlapally A. Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization. [Internet] [Thesis]. University of Missouri – Kansas City; 2017. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/10355/61852.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Charlapally A. Mitigation of Remanence Flux in Power Transformers using Predetermined Method of De-Energization. [Thesis]. University of Missouri – Kansas City; 2017. Available from: http://hdl.handle.net/10355/61852
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Oregon State University
22.
Audunsson, Haraldur.
Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava.
Degree: PhD, Geophysics, 1989, Oregon State University
URL: http://hdl.handle.net/1957/29359
► The Roza flow of the Columbia River Basalt group in Washington State U.S.A. extruded at about 15 Ma during intermediate geomagnetic polarity. The Roza is…
(more)
▼ The Roza flow of the Columbia River Basalt group in
Washington State U.S.A. extruded at about 15 Ma during
intermediate geomagnetic polarity. The Roza is underlain
by normal polarity flows and overlain by reversed units.
The Roza is an extensive flow, up to 60 in thick. As the
remanence-blocking isotherms progressed into the flow, it
recorded a short continuous segment of the transitional
geomagnetic field.
Our studies show limited thermal remagnetization in
the underlying flow, and we infer that groundwater was
effective in extracting the heat. The extent of basement
heating was further reduced by the insulating scoria
immediately beneath Roza. Hence, the Roza flow cooled
symmetrically from its top and base.
Samples from the drilicores acquired drilling induced
remanent
magnetization (DIRM), shown to be well modelled as
an isothermal remanent
magnetization produced in nonuniform
fields of the order of 10 mT at the rim of the drillstring.
Alternating field demagnetization was usually successful in
removing the DIRM.
The remanence stability is higher in the top third of
Roza, due to smaller magnetic particles, than in the lower
two thirds of the flow, where the magnetic properties are
nearly uniform. The stability profile corresponds to the
entablature/colonnade subdivision. High temperature
subsolidus oxidation of the titanomagnetites increased with
height in the flow, altering the primary symmetric
intraflow distribution.
The declination of the Roza flow sampled at numerous
outcrops is consistently about 189°. In a 54 m drillcore
section, Roza inclinations become more negative towards the
flow interior, consistent with its magnetostratigraphic
position. Superimposed is a symmetric, rapid change in
inclination from -2 to -15° and back to -5°. The flow's
thermal history predicts that these fluctuations have a
characteristic time between 15 and 60 years, such that the
inclination changed at a rate of 1/2 to 2° per year,
showing that the directions of this transitional field
fluctuated several times more rapidly than the present
geomagnetic field. However, considering the generally
reduced intensity during transitions, these fluctuations
might not be unusual.
Advisors/Committee Members: Levi, Shaul (advisor).
Subjects/Keywords: Thermoremanent magnetization – Columbia Plateau
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APA (6th Edition):
Audunsson, H. (1989). Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/29359
Chicago Manual of Style (16th Edition):
Audunsson, Haraldur. “Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava.” 1989. Doctoral Dissertation, Oregon State University. Accessed April 10, 2021.
http://hdl.handle.net/1957/29359.
MLA Handbook (7th Edition):
Audunsson, Haraldur. “Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava.” 1989. Web. 10 Apr 2021.
Vancouver:
Audunsson H. Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava. [Internet] [Doctoral dissertation]. Oregon State University; 1989. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1957/29359.
Council of Science Editors:
Audunsson H. Paleomagnetism, magnetic properties and thermal history of a thick transitional-polarity lava. [Doctoral Dissertation]. Oregon State University; 1989. Available from: http://hdl.handle.net/1957/29359
Vanderbilt University
23.
Janve, Vaibhav Anil.
Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis.
Degree: PhD, Physics, 2015, Vanderbilt University
URL: http://hdl.handle.net/1803/11234
► Conventional MRI is sensitive to detect brain abnormalities non-invasively through excellent contrast generated by variation in relaxation times and water proton density. However, conventional MRI…
(more)
▼ Conventional MRI is sensitive to detect brain abnormalities non-invasively through excellent contrast generated by variation in relaxation times and water proton density. However, conventional MRI lacks the specificity and quantitation to specific pathologies and tissue components such as myelin. Myelin is the major constituent of white matter ─an insulating macromolecular sleeve wrapped around axons of brain cells. Loss of white matter, specifically myelin leads to severe motor and cognitive deficits in diseases such as multiple sclerosis. Advanced quantitative MRI methods such as quantitative
magnetization transfer (qMT) and diffusion tensor imaging (DTI) have emerged as putative biomarkers that improve sensitivity, specificity and provide quantitative metrics to measure myelin. qMT and DTI are model based quantitative techniques, which provide sub-voxel information of the underlying tissue architecture. qMT is sensitive to the tissue macromolecular content, whereas DTI is sensitive to tissue microstructure. Pool size ratio (PSR, a qMT parameter) and radial diffusivity (RD, a DTI parameter) provide an indirect quantitative measure of myelin. However, their relative sensitivities and specificities to myelin are unclear. qMT and DTI are based on different physical principles and may provide complementary information. While histology is the gold standard for myelin quantification, it can only be performed postmortem or through invasive biopsies. Thus, systematic quantitative MRI and histological validation studies are essential to determine the specific sensitivities of non-invasive quantitative metrics. Although, limited data is available on such studies due to their tedious, time intensive and complex nature. My thesis work addresses this gap by performing quantitative MRI and histological validation on a relatively new animal model of multiple sclerosis (MS), which recapitulates the inflammatory and non-inflammatory demyelinating phases seen in patients. The animal model was characterized using structural MRI, qMRI and histological methods. To enable quantitative comparisons amongst MRI and histological parameters, detailed processing protocol were designed and implemented including 3D qMT and DTI protocols and histological pipeline. In vivo and ex vivo studies were performed and qMT and DTI metrics were correlated with histology and among each other to determine their specific sensitivities. Furthermore, in an attempt to translate the animal work to clinical settings, a fast qMT sequence with GRASE readout was tested on human scanners. In conclusion, we found that PSR, and RD are sensitive to histological myelin content with PSR having the strongest correlation.
Advisors/Committee Members: Adam W. Anderson (committee member), David J. Ernst (committee member), Mark D. Does (committee member), John C. Gore (committee member), Daniel F. Gochberg (Committee Chair).
Subjects/Keywords: MRI; magnetization transfer; diffusion; multiple sclerosis; qMT; DTI; quantitative
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APA (6th Edition):
Janve, V. A. (2015). Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis. (Doctoral Dissertation). Vanderbilt University. Retrieved from http://hdl.handle.net/1803/11234
Chicago Manual of Style (16th Edition):
Janve, Vaibhav Anil. “Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis.” 2015. Doctoral Dissertation, Vanderbilt University. Accessed April 10, 2021.
http://hdl.handle.net/1803/11234.
MLA Handbook (7th Edition):
Janve, Vaibhav Anil. “Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis.” 2015. Web. 10 Apr 2021.
Vancouver:
Janve VA. Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis. [Internet] [Doctoral dissertation]. Vanderbilt University; 2015. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1803/11234.
Council of Science Editors:
Janve VA. Myelin sensitivity in quantitative magnetization transfer and diffusion tensor imaging in an animal model of multiple sclerosis. [Doctoral Dissertation]. Vanderbilt University; 2015. Available from: http://hdl.handle.net/1803/11234
Vanderbilt University
24.
West, Kathryn Louise.
Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains.
Degree: PhD, Biomedical Engineering, 2016, Vanderbilt University
URL: http://hdl.handle.net/1803/14525
► Advanced neuroimaging techniques provide the possibility to non-invasively understand and monitor white matter during development and disease. While data from quantitative MRI techniques, such as…
(more)
▼ Advanced neuroimaging techniques provide the possibility to non-invasively understand and monitor white matter during development and disease. While data from quantitative MRI techniques, such as multiexponential T2 (MET2) and quantitative
magnetization transfer (qMT), correlate with myelin content, neither provide an absolute measure of the myelin volume fraction (MVF). Additionally, in preclinical studies, despite time-intensity and small tissue samples, histology remains the gold standard for quantitatively assessing changes in myelin content and white matter microstructural properties, such as myelin thickness and the g-ratio (ratio of axon radius to myelinated fiber radius). Therefore, the work in this dissertation first established and validated methods for MVF imaging from MET2 and qMT against quantitative electron microscopy. We show strong agreement in adult, control mice along with three mouse models of white matter disease. Next, we applied MVF imaging in mice during normal development and observe good agreement between MET2 and qMT and with expected myelin development. To further investigate specific changes in myelin microstructure, recent methods proposed measuring the g-ratio from MRI (gMRI). We revised the model and displayed with quantitative histology that gMRI provides an axon-area-weighted g-ratio. Calculating gMRI requires an accurate measure of MVF; thus, we utilize our MVF imaging techniques to measure gMRI in mouse brain and detect changes in g-ratio with disease in agreement with quantitative histology. In short, we develop and validate measures of MVF and g-ratio from MRI which have the potential to non-invasively provide more specific and thorough assessment of white matter not obtainable with currently used methods.
Advisors/Committee Members: Adam W. Anderson (committee member), Kevin C. Ess (committee member), Daniel F. Gochberg (committee member), John C. Gore (committee member), Mark D. Does (Committee Chair).
Subjects/Keywords: magnetization transfer; multiexponential T2; myelin; MRI; neuroimaging; histology; g-ratio
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APA ·
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MLA ·
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APA (6th Edition):
West, K. L. (2016). Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains. (Doctoral Dissertation). Vanderbilt University. Retrieved from http://hdl.handle.net/1803/14525
Chicago Manual of Style (16th Edition):
West, Kathryn Louise. “Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains.” 2016. Doctoral Dissertation, Vanderbilt University. Accessed April 10, 2021.
http://hdl.handle.net/1803/14525.
MLA Handbook (7th Edition):
West, Kathryn Louise. “Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains.” 2016. Web. 10 Apr 2021.
Vancouver:
West KL. Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains. [Internet] [Doctoral dissertation]. Vanderbilt University; 2016. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1803/14525.
Council of Science Editors:
West KL. Development and Evaluation of Relaxation-Based Measures of Myelin Content and Microstructure in Rodent Brains. [Doctoral Dissertation]. Vanderbilt University; 2016. Available from: http://hdl.handle.net/1803/14525
25.
Kneip, Martin K.
Magnetization dynamics in diluted
magnetic semiconductor heterostructures.
Degree: 2008, Technische Universität Dortmund
URL: http://hdl.handle.net/2003/25822
Subjects/Keywords: DMS; Magnetization dynamics;
Spintronics; 530
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APA (6th Edition):
Kneip, M. K. (2008). Magnetization dynamics in diluted
magnetic semiconductor heterostructures. (Thesis). Technische Universität Dortmund. Retrieved from http://hdl.handle.net/2003/25822
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kneip, Martin K. “Magnetization dynamics in diluted
magnetic semiconductor heterostructures.” 2008. Thesis, Technische Universität Dortmund. Accessed April 10, 2021.
http://hdl.handle.net/2003/25822.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kneip, Martin K. “Magnetization dynamics in diluted
magnetic semiconductor heterostructures.” 2008. Web. 10 Apr 2021.
Vancouver:
Kneip MK. Magnetization dynamics in diluted
magnetic semiconductor heterostructures. [Internet] [Thesis]. Technische Universität Dortmund; 2008. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/2003/25822.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kneip MK. Magnetization dynamics in diluted
magnetic semiconductor heterostructures. [Thesis]. Technische Universität Dortmund; 2008. Available from: http://hdl.handle.net/2003/25822
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Leiden University
26.
Soest, Jean-Paul van.
Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM.
Degree: 2020, Leiden University
URL: http://hdl.handle.net/1887/87436
► Various experiments have indicated that electron transfer through nonmagnetic chiral hydrocarbon molecules is spin dependent. This property is called the chiral-induced spin selectivity (CISS) effect…
(more)
▼ Various experiments have indicated that electron transfer through nonmagnetic chiral hydrocarbon molecules is spin dependent. This property is called the chiral-induced spin selectivity (CISS) effect and its presence cannot be explained with current theoretical models. To detect the CISS effect experimentally, chiral molecules have to be isolated. Therefore, transport through a single chiral molecule must be measured with STM. A fabrication procedure for sharp and stable nickel STM tips has been developed using electrochemical etching. The produced tips are very sharp and have an average opening angle of 18.9° and an apex size below 200 nm. The magnetic polarisation of the tip can be reversed in situ by a magnetic field, induced by a coil around the tip, which has been demonstrated. The quality and the magnetisation of the tips have been tested on HOPG, gold and nickel with STM. Clear large-scale images were obtained on all materials. Atomic resolution was obtained on HOPG. With these challenges resolved, STM measurements using a nickel tip with both magnetic polarisations can be performed in the study of single chiral molecules as spin filter and the investigation of the CISS effect.
Advisors/Committee Members: Ruitenbeek, Jan van (advisor).
Subjects/Keywords: CISS; STM; magnetization; fabrication; STM tip; etching; spin polarized; spin
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APA (6th Edition):
Soest, J. v. (2020). Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM. (Masters Thesis). Leiden University. Retrieved from http://hdl.handle.net/1887/87436
Chicago Manual of Style (16th Edition):
Soest, Jean-Paul van. “Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM.” 2020. Masters Thesis, Leiden University. Accessed April 10, 2021.
http://hdl.handle.net/1887/87436.
MLA Handbook (7th Edition):
Soest, Jean-Paul van. “Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM.” 2020. Web. 10 Apr 2021.
Vancouver:
Soest Jv. Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM. [Internet] [Masters thesis]. Leiden University; 2020. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/1887/87436.
Council of Science Editors:
Soest Jv. Fabrication and Magnetisation of Electrochemically Etched Nickel Tips for Spin-Polarised STM. [Masters Thesis]. Leiden University; 2020. Available from: http://hdl.handle.net/1887/87436
27.
Kneip, Martin K.
Magnetization dynamics in diluted magnetic semiconductor heterostructures.
Degree: 2008, Technische Universität Dortmund
URL: http://dx.doi.org/10.17877/DE290R-8392
Subjects/Keywords: Magnetization dynamics; DMS; Spintronics; 530
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kneip, M. K. (2008). Magnetization dynamics in diluted magnetic semiconductor heterostructures. (Doctoral Dissertation). Technische Universität Dortmund. Retrieved from http://dx.doi.org/10.17877/DE290R-8392
Chicago Manual of Style (16th Edition):
Kneip, Martin K. “Magnetization dynamics in diluted magnetic semiconductor heterostructures.” 2008. Doctoral Dissertation, Technische Universität Dortmund. Accessed April 10, 2021.
http://dx.doi.org/10.17877/DE290R-8392.
MLA Handbook (7th Edition):
Kneip, Martin K. “Magnetization dynamics in diluted magnetic semiconductor heterostructures.” 2008. Web. 10 Apr 2021.
Vancouver:
Kneip MK. Magnetization dynamics in diluted magnetic semiconductor heterostructures. [Internet] [Doctoral dissertation]. Technische Universität Dortmund; 2008. [cited 2021 Apr 10].
Available from: http://dx.doi.org/10.17877/DE290R-8392.
Council of Science Editors:
Kneip MK. Magnetization dynamics in diluted magnetic semiconductor heterostructures. [Doctoral Dissertation]. Technische Universität Dortmund; 2008. Available from: http://dx.doi.org/10.17877/DE290R-8392
28.
Lebrun, Romain.
Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle.
Degree: Docteur es, Physique, 2015, Université Paris-Saclay (ComUE)
URL: http://www.theses.fr/2015SACLS233
► La découverte de la magnétorésistance géante en 1988 est considérée comme la date de naissance d’un nouveau et dynamique champ de recherche appelé l’électronique de…
(more)
▼ La découverte de la magnétorésistance géante en 1988 est considérée comme la date de naissance d’un nouveau et dynamique champ de recherche appelé l’électronique de spin. La riche physique associée au transport de spin devrait révolutionner le futur de la nanoélectronique. Dans ce cadre les nano-oscillateurs à transfert de spin (STOs) se sont positionnés comme des candidats sérieux pour le développement d’une nouvelle génération de dispositifs rf basés sur l’électronique de spin.Au début de ma thèse, l’important bruit de phase des STOs restait une contrainte majeure limitant les perspectives technologiques à ce type d’oscillateurs. Dans cette thèse nous avons cherché à contrôler la dynamique des STOs et à réduire leur bruit phase en développant différentes stratégies : (i) l’optimisation des propriétés des matériaux magnétiques utilisés (ii) l’excitation de modes couplés dans des systèmes hybridés (iii) la stabilisation de la dynamique de la phase d’un STO avec un signal extérieur de référence (iv) la synchronisation mutuelle de différents oscillateurs pour améliorer la cohérence spectrale et la puissance des STOs. Nous focalisons en particulier sur le cas de STO à base de vortex magnétique qui présentent intrinsèquement des cohérences spectrales plus élevées que celles d’autres types d’oscillateurs.Dans une première partie, nous nous proposons d’identifier et d’étudier les différents mécanismes qui régissent et contrôle la dynamique d’un STO à base de vortex magnétique dans les régimes auto-oscillant et non-autonomes. Nous mettons tout d’abord en évidence que l’excitation de modes couplés permet de contrôler les propriétés rf d’un oscillateur unique en prenant l’exemple d’un STO à base de deux vortex magnétiques couplés. Par la suite, nous étudions la synchronisation « parfaite » de ces STOs à base de vortex avec un courant rf de référence. Nous corrélons l’observation d’une largeur de raie d’un hertz et d’un bruit de phase minimum de -90 dBc/Hz à 1kHz de la porteuse dans l’état synchronisé à une absence de glissement de phase, i.e. à l’absence de phénomène de désynchronisation. Le fort couple de Field-like planaire mesuré dans ces STOs représente un outil précieux pour contrôler le processus de synchronisation. Dans le cas des STOs à double vortex, un tel contrôle nous permet d’observer des phénomènes physiques exotiques allant de la synchronisation simultanée de plusieurs modes, à de l’auto-synchronisation en passant par des dynamiques de synchronisation incohérentes.Dans une seconde partie, nous proposons différents concepts innovants de dispositifs rf à base de vortex magnétique. Nous présentons tout d’abord les bases d’une boucle à retard de phase permettant d’asservir un STO. En prenant avantage du fort couple de Field Like, nous développons un nouveau schéma de détection rf, plus efficace que les actuelles diodes Schottky, basé sur un renversement d’aimantation en expulsant réversiblement le cœur de vortex à l’aide d’un courant rf. Finalement, nous démontrons qu’il est possible de synchroniser électriquement…
Advisors/Committee Members: Cros, Vincent (thesis director).
Subjects/Keywords: Spintronique; Oscillateur; Magnétisme; Synchronisation; Spintronic; Oscillator; Magnetization; Synchronization
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APA ·
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APA (6th Edition):
Lebrun, R. (2015). Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2015SACLS233
Chicago Manual of Style (16th Edition):
Lebrun, Romain. “Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle.” 2015. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed April 10, 2021.
http://www.theses.fr/2015SACLS233.
MLA Handbook (7th Edition):
Lebrun, Romain. “Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle.” 2015. Web. 10 Apr 2021.
Vancouver:
Lebrun R. Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2015. [cited 2021 Apr 10].
Available from: http://www.theses.fr/2015SACLS233.
Council of Science Editors:
Lebrun R. Coupled vortex dynamics in spin-torque oscillators : from resonant excitation to mutual synchronization : Vortex magnétiques couplés dans des oscillateurs à transfert de spin : de l'excitation résonante à la synchronisation mutuelle. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2015. Available from: http://www.theses.fr/2015SACLS233
Colorado State University
29.
Liu, Hau-Jian Jason.
Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films.
Degree: PhD, Physics, 2014, Colorado State University
URL: http://hdl.handle.net/10217/83759
► This thesis focuses on the use of the Brillouin light scattering (BLS) technique to measure spin waves or magnons in thin films. BLS is an…
(more)
▼ This thesis focuses on the use of the Brillouin light scattering (BLS) technique to measure spin waves or magnons in thin films. BLS is an experimental technique that measures the inelastically scattered light from photon-magnon interactions. Broadly, three different experiments are presented in this thesis: the measurements of spin wave properties in iron cobalt (FeCo), yttrium iron garnet (YIG), and microstructures involving Permalloy (Ni80Fe20) and cobalt nickel (CoNi). First, conventional backward scattering BLS was used to measure the spin waves in a set of Fe65Co35 films that were provided by Seagate Technologies. By fitting the spin wave frequencies that were measured as a function of the external magnetic field and film thickness, the quantum mechanical parameter responsible for short range order, known as the exchange parameter, was determined. Second, nonlinear spin waves were measured in YIG using conventional forward scattering BLS with time resolution. Two nonlinear three wave processes were observed, namely, the three magnon splitting and confluence. The nonlinear power threshold, the saturation
magnetization, and the film thickness were determined independently using network analyzer measurements. The spin wave group velocities were determined from the space- and time-resolved BLS data and compared to calculations from the dispersion relations. Back calculations showed the location where the three magnon splitting process took place. Lastly, spin waves in Permalloy and CoNi microstrips were measured using a recently developed micro-BLS. The micro-BLS, with a spatial resolution of 250 nm, allows for measuring the effects on the lateral confinement of spin waves in microstrips. The confinement of spin waves led to modifications to the dispersion relations, which were compared against the spin wave frequencies obtained from the micro-BLS. The Permalloy experiments shows non-reciprocity in surface spin wave modes with opposite wavevectors and provides a quantitative measure of the difference in excitation efficiency between the surface spin wave and the backward volume spin wave modes. Measurements were also conducted in the Permalloy microstrips at zero external magnetic field, showing evidence that propagating spin waves can be observed by exploiting the effects of shape anisotropy. Finally, preliminary measurements were done on CoNi microstrips with perpendicular anisotropy. A magnetic signal was detected, however further investigation will be needed to determine the exact origin of the observed signal and to definitively answer the question as to whether or not BLS can be used to measure spin waves in perpendicularly magnetized films. Overall, the experiments and results presented in this thesis show that BLS is a useful tool for measuring spin wave properties in magnetic thin films.
Advisors/Committee Members: Buchanan, Kristen S. (advisor), Gelfand, Martin P. (committee member), Kabos, Pavel (committee member), Neilson, James R. (committee member).
Subjects/Keywords: Brillouin light scattering; magnetic materials; magnetization dynamics; microstructures; nanoscience; spin waves
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APA ·
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APA (6th Edition):
Liu, H. J. (2014). Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/83759
Chicago Manual of Style (16th Edition):
Liu, Hau-Jian Jason. “Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films.” 2014. Doctoral Dissertation, Colorado State University. Accessed April 10, 2021.
http://hdl.handle.net/10217/83759.
MLA Handbook (7th Edition):
Liu, Hau-Jian Jason. “Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films.” 2014. Web. 10 Apr 2021.
Vancouver:
Liu HJ. Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films. [Internet] [Doctoral dissertation]. Colorado State University; 2014. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/10217/83759.
Council of Science Editors:
Liu HJ. Brillouin light scattering study of linear and nonlinear spin waves in continuous and patterned magnetic thin films. [Doctoral Dissertation]. Colorado State University; 2014. Available from: http://hdl.handle.net/10217/83759
University of Adelaide
30.
Nguyen, Van Tai.
Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization.
Degree: 2019, University of Adelaide
URL: http://hdl.handle.net/2440/119972
► Cylindrical/ring-shaped permanent magnets with diametrical magnetization can be found in many applications, ranging from electrical motors to position sensory systems. In order to calculate the…
(more)
▼ Cylindrical/ring-shaped permanent magnets with diametrical
magnetization can be found in many applications, ranging from electrical motors to position sensory systems. In order to calculate the magnetic field generated by a permanent magnet of this kind correctly and with low computational cost, several studies have been reported in the literature providing analytical expressions. However, these analytical expressions are either limited for an infinite cylinder or for computing the magnetic field only on the central axis of a finite cylinder. The others are derived to calculate the magnetic field at any point in three-dimensional (3D) space but only with low accuracy. This thesis presents an exact analytical model of the magnetic field generated by a diametrically magnetized cylindrical/ring-shaped permanent magnet with a limited length, which can be used to calculate the magnetic field of any point in 3D space fast and with very high accuracy. The expressions were analytically derived, based on geometrical analysis without calculating the magnetic scalar potential. Also, there is no approximation in the derivation steps that yields the exact analytical model. Three components of the magnetic field are analytically represented using complete and incomplete elliptical integrals, which are robust and have low computational cost. The accuracy and efficiency of the developed analytical model was validated using Finite Element Analysis and compared against existing models.
Advisors/Committee Members: Lu, Tien-Fu (advisor), School of Mechanical Engineering (school).
Subjects/Keywords: analytical expression; diametrical magnetization; permanent magnet; magnetic field
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APA (6th Edition):
Nguyen, V. T. (2019). Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/119972
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Nguyen, Van Tai. “Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization.” 2019. Thesis, University of Adelaide. Accessed April 10, 2021.
http://hdl.handle.net/2440/119972.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Nguyen, Van Tai. “Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization.” 2019. Web. 10 Apr 2021.
Vancouver:
Nguyen VT. Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization. [Internet] [Thesis]. University of Adelaide; 2019. [cited 2021 Apr 10].
Available from: http://hdl.handle.net/2440/119972.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Nguyen VT. Modelling of Magnetic Fields of Permanent Magnets with Diametrical Magnetization. [Thesis]. University of Adelaide; 2019. Available from: http://hdl.handle.net/2440/119972
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
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Open Access Theses and Dissertations
