subject:(Verwey)

1. Bjork, Andreas. Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget.

Degree: Geophysics, 2018, Uppsala University

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-347975

►

Laboratory magnetic measurements are used to develop a methodology to characterize the Kiruna-type Rare Earth Elements (REE) bearing apatite iron-oxide deposits at Blötberget in… (more)

▼

Laboratory magnetic measurements are used to develop a methodology to characterize the Kiruna-type Rare Earth Elements (REE) bearing apatite iron-oxide deposits at Blötberget in central Sweden. This high-grade ore deposit is known to have sharp boundaries between lens shaped main ore bodies of magnetite-rich ore, and a complex hematite-rich ore associated with pegmatites and skarn formation. The thesis covers laboratory magnetic measurements of 37 samples originating from eight drill cores and reference samples from previously mined area. It focuses on on-covering how the samples relate in terms of magnetic susceptibility, further its dependency on temperature, frequency, field and the orientation. The results are correlated with petrographic analysis previously performed on accompanying thin sections. The measurements show that magnetite with strong susceptibility contribution overshadow the hematite contribution in the samples. Transition changes in susceptibility are noticeable when crossing the Verwey temperature; -153°C, Curie temperature; 580°C and Néel temperature; 680°C. The Morin temperature appears at -60°C, or is missing. Linear relationships are identified between the magnitude difference in susceptibilities across transitions at high temperature and wt% magnetite and hematite have been identified. The Blötberget skarn and hematite-rich ore samples have a higher degree of susceptibility anisotropy than the other ore-types. Blötberget samples are dominated by multidomain characteristics in remanence, saturation and coercivity. High temperature measurements have shown that the magnetite is close to pure. The low temperature measurements suggest hematite is impure or bears a petrological footprint. The study also shows that rich iron ore samples sometimes can be at risk of being overlooked with standard methods of measuring susceptibility

Laboratorietekniska metoder kan användas som ett komplement till malmgeologi och geofysisk prospektering. I denna metodstudie karaktäriseras apatitjärnmalm från Blötberget, nära Grängesberg. En fyndighet bestående av linsformade malmkroppar rika på magnetit och ofta avskilda men komplexa hematitrika stråk. Studien är gjord 37 prover från totalt 8 borrkärnor, och lokaler som tillhörde produktion från gruvverksamhet under 1900-talet. Mätmetoderna fokuserar på att kartlägga malmens magnetiska egenskaper, och hur temperatur, frekvens, fältstyrka samt riktning påverkar dessa. Resultaten jämfördes med tidigare petrografisk studie av tillhörande tunnslip Resultaten visar att magnetit står för merparten av susceptibiliteten i proverna, men att även hematit kan urskiljas och kvantifieras. Temperaturberoende har påvisats vid övergångar för Verwey-temperatur; -153°C, Curie-temperatur; 580 °C, och Néeltemperatur; 680 °C. Den förväntade Morin-temperaturen vid -14°C, påträffades vid -60 °C eller saknas helt för flera av de hematitrika proverna. Magnetiskt anisotropa prover återfinns bland prover som identifierats som skarn eller hematitrika. Magnetisk…

Subjects/Keywords: Verwey; Morin; Curie; Néel; magnetite; hematite; alteration; iron-ore; quality control; kappabridge; hysteresis; susceptibility; anisotropy; Verwey; Morin; Curie; Néel; magnetit; hematit; oxidation; järnmalm; kvalitetskontroll; kappabridge; hysteresis; susceptibilitet; anisotropi; Geophysics; Geofysik

11 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bjork, A. (2018). Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget. (Thesis). Uppsala University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-347975

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bjork, Andreas. “Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget.” 2018. Thesis, Uppsala University. Accessed January 22, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-347975.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bjork, Andreas. “Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget.” 2018. Web. 22 Jan 2021.

Vancouver:

Bjork A. Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget. [Internet] [Thesis]. Uppsala University; 2018. [cited 2021 Jan 22]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-347975.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bjork A. Characterizing magnetic susceptibility and remanent magnetization of magnetite and hematite rich drill-core samples at Blötberget. [Thesis]. Uppsala University; 2018. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-347975

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of New South Wales

2. Chang, Fenfen. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.

Degree: Physics, 2017, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

► Multiferroics exhibit tremendous potential in technological applications, of which the interplaybetween the ferro-/antiferromagnetic, ferroelectricity, and ferroelasticity can be manipulatedby external parameters such as electric or… (more)

▼ Multiferroics exhibit tremendous potential in technological applications, of which the interplaybetween the ferro-/antiferromagnetic, ferroelectricity, and ferroelasticity can be manipulatedby external parameters such as electric or magnetic fields and even can be created byproper control of internal parameters, such as oxygen-content, cation doping, and internalpressure. Invaluable insight into the multiferroicity can be provided by investigating the roleof such parameters in the crystallographic and magnetic structures of transition metal oxides.In this thesis, a comprehensive studies of contribution of oxygen-deficiencies and cation dopingto the various phases are presented, which utilize the neutron and synchrotron powderdiffraction.The multivalent nature of cobalt ions in SrCoO3􀀀d causes an oxygen-content dependentphase diagram. It is vital to determine the precise crystallographic and magnetic structure ofoxygen-vacancy ordered SrCoO3􀀀d , which provides prerequisite to reveal the mechanism ofits multiferroicity in the corresponding thin film samples. Using the neutron and synchrotronpowder diffraction techniques, the correct space group and precise magnetic structures aredetermined for the different oxygen-vacancy ordered phases: the brownmillerite SrCoO2:5,the tetragonal SrCoO2:875, and the cubic SrCoO3.Ferroelectricity can be induced by the canted spin configuration, which exists widely inthe frustrated spin systems. With such an expectation, Zn-substituted CuFe2O4 was studiedand a comprehensive phase diagram was built for Cu1􀀀xZnxFe2O4. Spin canting couldlead to a spin spiral phase which could possibly induce a multiferroic state as observed inCuFeO2. The purpose of this project was to further investigate the spin canting in ZndopedCuFe2O4 and elucidate the possibility of multiferroicity in this system. Furthermore,pure ZnFe2O4 is already an interesting highly frustrated spin system. Magnetite is the oldestknown magnet. As the first known multiferroics, the ferroelectricity in Fe3O4 is drivenby the Verwey transition. However, the microscopic origin of the Verwey transition in Fe3O4is still in debate. In order to obtain a deeper insight into the mechanism of the charge ordering,Cu-doped Fe3O4 was investigated using the high-resolution neutron and synchrotrondiffraction. The main emphasis was the stability of the Verwey transition with charge carrierdoping. Advisors/Committee Members: Ulrich, Clemens, Physics, Faculty of Science, UNSW, Sushkov, Oleg, Physics, Faculty of Science, UNSW.

Subjects/Keywords: Oxygen vacancy ordering; Neutron diffraction; Synchrotron powder diffraction; Verwey transition; Charge ordering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chang, F. (2017). Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

Chicago Manual of Style (16^th Edition):

Chang, Fenfen. “Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.” 2017. Doctoral Dissertation, University of New South Wales. Accessed January 22, 2021. http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true.

MLA Handbook (7^th Edition):

Chang, Fenfen. “Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.” 2017. Web. 22 Jan 2021.

Vancouver:

Chang F. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. [Internet] [Doctoral dissertation]. University of New South Wales; 2017. [cited 2021 Jan 22]. Available from: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true.

Council of Science Editors:

Chang F. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. [Doctoral Dissertation]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

3. Terrier, Erwan. Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures.

Degree: Docteur es, Physique de la matière condensée, 2016, Université de Strasbourg

URL: http://www.theses.fr/2016STRAE010

►

Ce travail de thèse traite de la dynamique ultrarapide de spins et de charges dans des oxydes de fer. Dans un premier temps, on montre… (more)

▼

Ce travail de thèse traite de la dynamique ultrarapide de spins et de charges dans des oxydes de fer. Dans un premier temps, on montre à l'aide d'un montage pompe-sonde résolu en temps et exploitant l'effet Faraday magnéto-optique, que le temps de désaimantation dans une assemblée de nanoparticules de maghémite est plus rapide que le temps de désaimantation dans une assemblée de nanoparticules de magnétite. Une superposition des temps de thermalisation des électrons et de désaimantation est observée dans la maghémite. Cette accélération du temps de désaimantation est interprétée comme étant la conséquence d'un renforcement des interactions antiferromagnétiques dans la maghémite. La seconde partie prouve qu'il est possible de caractériser la transition de Verwey dans un film de magnétite grâce à des signaux de dynamique de charges et de spins. La dynamique ultrarapide d'aimantation se caractérise par un mouvement de précession dépendant de la température. D'importantes modifications des oscillations sont visibles de part et d'autre de la température de Verwey, reflétant un changement d'anisotropie caractéristique de cette transition.

This work deals with spins and charges ultrafast dynamics in iron oxide. Thanks to a time-resolved magneto-optical Faraday effect measurements, we show the demagnetization time in an assembly of maghemite nanoparticles is faster than the demagnetization time in an assembly of magnetite nanoparticles. A superposition of thermalization times of electron and demagnetization times is observed in maghemite. This acceleration of the demagnetization time is interpreted as the effect of an enhancement of antiferromagnetic interactions in maghemite. The second part demonstrates the possibility to characterize the Verwey transition in a thin film of magnetite thanks to charges and spins dynamics signals. The ultrafast magnetization dynamic shows a temperature-dependent precession motion. Huge modifications of oscillations are visible on both side of Verwey temperature, reflecting an anisotropy change typical of this transition.

Advisors/Committee Members: Halté, Valérie (thesis director).

Subjects/Keywords: Femtomagnétisme; Magnétite; Maghémite; Nanoparticules; Temps de désaimantation; Interactions d’échange; Transition de Verwey; Femtomagnetism; Magnetite; Maghemite; Nanoparticles; Démagnetization time; Exchange interaction; Verwey transition; 530.41

…O4 débute réellement en 1934 quand Evert Verwey découvre que ce matériau présente une… …évidence la transition isolant/métal définie comme étant la transition de Verwey via une…

11 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Terrier, E. (2016). Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures. (Doctoral Dissertation). Université de Strasbourg. Retrieved from http://www.theses.fr/2016STRAE010

Chicago Manual of Style (16^th Edition):

Terrier, Erwan. “Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures.” 2016. Doctoral Dissertation, Université de Strasbourg. Accessed January 22, 2021. http://www.theses.fr/2016STRAE010.

MLA Handbook (7^th Edition):

Terrier, Erwan. “Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures.” 2016. Web. 22 Jan 2021.

Vancouver:

Terrier E. Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures. [Internet] [Doctoral dissertation]. Université de Strasbourg; 2016. [cited 2021 Jan 22]. Available from: http://www.theses.fr/2016STRAE010.

Council of Science Editors:

Terrier E. Désaimantation induite par impulsions laser femtosecondes dans des nanostructures d'oxyde de fer : Femtosecond laser-induced demagnetization in iron oxide nanostructures. [Doctoral Dissertation]. Université de Strasbourg; 2016. Available from: http://www.theses.fr/2016STRAE010

University of Minnesota

4. Lindquist, Anna K. Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects.

Degree: PhD, Geophysics, 2013, University of Minnesota

URL: http://purl.umn.edu/159854

► Magnetite (Fe₃O₄) is the most important mineral to the rock magnetic and paleomagnetic communities and is ubiquitous in igneous, sedimentary, and metamorphic rocks. Larger multidomain… (more)

▼ Magnetite (Fe₃O₄) is the most important mineral to the rock magnetic and paleomagnetic communities and is ubiquitous in igneous, sedimentary, and metamorphic rocks. Larger multidomain (MD) magnetite grains are more common than single domain grains, so understanding how they record paleomagnetic fields would be a boon to paleomagnetists. MD magnetite grains are divided into multiple domains, regions with uniform magnetization, separated by domain walls. Domain walls sweep through magnetite grains easily, so slight changes in ambient magnetic fields can alter the magnetization of MD magnetite. Because of this, MD magnetite is not considered reliable for paleomagnetic studies, and the mechanisms by which MD grains may record past magnetic fields are not well understood. Dislocations, linear crystallographic defects, may increase magnetic coercivity by pinning domain walls in place. This study, for the first time, experimentally investigates this pinning behavior by using a transmission electron microscope (TEM) to simultaneously image magnetic domain walls, dislocations, and low-temperature twin structures. Magnetite grains were deformed in the dislocation glide regime, which is active in natural magnetite grains. Dislocations were not uniformly distributed throughout the sample, but regions with more and longer dislocations pinned domain walls more strongly. First-order reversal curve diagrams demonstrate the presence of regions with pinning strengths of over 125 mT. The strength of domain wall pinning at dislocations was found experimentally and theoretically to be proportional to dislocation length, with longer dislocations pinning more strongly. Average pinning fields were around 0.2 mT. Magnetite grains with more uniformly distributed dislocations would likely have coercivities that were high enough to enable MD magnetite to record geomagnetic fields over geologic timescales. Further, low-temperature TEM and magnetic studies demonstrated that dislocations can affect twin growth in magnetite below the Verwey transition. Deformed magnetite samples had more soft-shouldered Verwey transitions and were able to retain more remanence after low-temperature demagnetization (LTD). Therefore, MD magnetite grains may be able to retain relevant magnetizations, even after LTD. Dislocation length, density, and distribution are then all important considerations when investigating the ways in which MD magnetite may retain a stable record of paleomagnetic field characteristics, even after LTD.

Subjects/Keywords: Geophysics; Dislocation; Domain wall; Magnetite; Multidomain; Transmission electron microscopy; Verwey

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lindquist, A. K. (2013). Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects. (Doctoral Dissertation). University of Minnesota. Retrieved from http://purl.umn.edu/159854

Chicago Manual of Style (16^th Edition):

Lindquist, Anna K. “Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects.” 2013. Doctoral Dissertation, University of Minnesota. Accessed January 22, 2021. http://purl.umn.edu/159854.

MLA Handbook (7^th Edition):

Lindquist, Anna K. “Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects.” 2013. Web. 22 Jan 2021.

Vancouver:

Lindquist AK. Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects. [Internet] [Doctoral dissertation]. University of Minnesota; 2013. [cited 2021 Jan 22]. Available from: http://purl.umn.edu/159854.

Council of Science Editors:

Lindquist AK. Dislocations in Magnetite: Experimental Observations of their Structural, Magnetic, and Low-temperature Effects. [Doctoral Dissertation]. University of Minnesota; 2013. Available from: http://purl.umn.edu/159854

5. Senn, Mark Stephen. Charge, orbital and magnetic ordering in transition metal oxides.

Degree: PhD, 2013, University of Edinburgh

URL: http://hdl.handle.net/1842/7828

► Neutron and x-ray diffraction has been used to study charge, orbital and magnetic ordering in some transition metal oxides. The long standing controversy regarding the… (more)

▼ Neutron and x-ray diffraction has been used to study charge, orbital and magnetic ordering in some transition metal oxides. The long standing controversy regarding the nature of the ground state (Verwey structure) of the canonical charge ordered material magnetite (Fe3O4) has been resolved by x-ray single crystal diffraction studies on an almost single domain sample at 90 K. The Verwey structure is confirmed to have Cc symmetry with 56 unique sites in the asymmetric unit. Charge ordering is shown to be a useful first approximation to describe the nature of the ground state, and the conjecture that Verwey made in 1939 has finally been confirmed. However, three-site distortions which couple to the orbital ordering of the Fe2+ ordered states (trimerons) are shown to provide a more complete description of the low temperature structure. Trimerons explain the rather continuous distribution of the valence states observed in magnetite below Tv, anomalous shortening of Fe-Fe distances and the off-centre distortions resulting in ferroelectricity. DFT+U electronic structure calculations on the experimental coordinates support the conclusion of this crystallographic study, with the highest electron densities calculated for those Fe-Fe distances predicated to participate in the trimeron bonds. The 6H-perovskites of the type Ba3ARu2O9 have been reinvestigated by high resolution neutron and x-ray power diffraction. The charge ordered state of Ba3NaRu2O9 has been characterised at 110 K (P2/c, a =5.84001(2) Å, b = 10.22197(4) Å, c = 14.48497(6) Å, β = 90.2627(3) °) and shown to consist of a structure with near integer charge ordering of Ru5+ 2O9 / Ru6+ 2O9 dimers. The ground state has been shown to be very sensitive to external perturbations, with a novel melting of charge ordering observed under x-ray irradiation below 40 K (C2/c, a =5.84470(2) Å, b = 10.17706(3) Å, c = 14.45866(5) Å, β = 90.2151(3)-° at 10 K). High pressure studies reveal that the Ru-Ru intra-dimer distance may dictate the response of the system to pressure. Empirical trends in the Ba3ARu2O9 series of compounds have shown that change in ‘chemical pressure’ in these systems may be rationalised in terms of Coulomb’s law. In A = La and Y the magnetic ordering is shown to be FM within the Ru2O9 dimers (1.4(2) μB and 0.5(1) μB, respectively per Ru), representing the first case of intra dimer FM coupling reported in a system containing face-sharing RuO6 octahedra . The overall AFM coupling of the dimers implies an as yet unobserved breaking of the parent symmetry. In A = Nd, a complex competition between the crystal field effect of Nd3+ and the magnetic ordering of the Ru2O9 FM moments has been observed, leading first vi to FM order of Nd at 25 K (1.56(7) μB) followed by ordering of Ru moments (0.5(1) μB) and a spin reorientation transition of Nd moments at 18 K. In A = Ca, the formation of a singlet ground state is observed in Ru2O9 rather than the expected AFM coupling and below 100 K Ba3CaRu2O9 is diamagnetic. All five systems indicate that the Ru2O9 dimer is the…

Subjects/Keywords: 661; transition metal oxides; Charge ordering; Verwey structure; orbital ordering; trimerons

…28 Section B: The Verwey structure of Magnetite… …30 2. Introduction to spinels and the Verwey transition… …30 2.2. Magnetite and the Verwey transition… …41 Solution of the Verwey structure of magnetite by single crystal x-ray diffraction... 45… …59 3.3.3. Validation of the final model of the Verwey structure…

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Senn, M. S. (2013). Charge, orbital and magnetic ordering in transition metal oxides. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/7828

Chicago Manual of Style (16^th Edition):

Senn, Mark Stephen. “Charge, orbital and magnetic ordering in transition metal oxides.” 2013. Doctoral Dissertation, University of Edinburgh. Accessed January 22, 2021. http://hdl.handle.net/1842/7828.

MLA Handbook (7^th Edition):

Senn, Mark Stephen. “Charge, orbital and magnetic ordering in transition metal oxides.” 2013. Web. 22 Jan 2021.

Vancouver:

Senn MS. Charge, orbital and magnetic ordering in transition metal oxides. [Internet] [Doctoral dissertation]. University of Edinburgh; 2013. [cited 2021 Jan 22]. Available from: http://hdl.handle.net/1842/7828.

Council of Science Editors:

Senn MS. Charge, orbital and magnetic ordering in transition metal oxides. [Doctoral Dissertation]. University of Edinburgh; 2013. Available from: http://hdl.handle.net/1842/7828

University of South Florida

6. Siyambalapitiya, Chamila S. Growth and physical properties of magnetite thin films.

Degree: 2006, University of South Florida

URL: https://scholarcommons.usf.edu/etd/2705

► This project focused on two aspects of magnetite thin films. The first was to find optimum parameters and conditions for deposition of stoichiometeric Magnetite films… (more)

Subjects/Keywords: PLD; Magnetite; Verwey; M-H loops; Magneto-resistance; IV; American Studies; Arts and Humanities

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Siyambalapitiya, C. S. (2006). Growth and physical properties of magnetite thin films. (Thesis). University of South Florida. Retrieved from https://scholarcommons.usf.edu/etd/2705

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Siyambalapitiya, Chamila S. “Growth and physical properties of magnetite thin films.” 2006. Thesis, University of South Florida. Accessed January 22, 2021. https://scholarcommons.usf.edu/etd/2705.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Siyambalapitiya, Chamila S. “Growth and physical properties of magnetite thin films.” 2006. Web. 22 Jan 2021.

Vancouver:

Siyambalapitiya CS. Growth and physical properties of magnetite thin films. [Internet] [Thesis]. University of South Florida; 2006. [cited 2021 Jan 22]. Available from: https://scholarcommons.usf.edu/etd/2705.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Siyambalapitiya CS. Growth and physical properties of magnetite thin films. [Thesis]. University of South Florida; 2006. Available from: https://scholarcommons.usf.edu/etd/2705

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Oxford

7. Muxworthy, Adrian R. Stability of magnetic remanence in multidomain magnetite.

Degree: PhD, 1998, University of Oxford

URL: http://ora.ox.ac.uk/objects/uuid:bc70e665-4c54-4ab5-98fa-d43ccecd07a1 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390505

► If a rock is to retain a geologically meaningful magnetic record of its history, it is essential that it contains magnetic minerals which are capable… (more)

▼ If a rock is to retain a geologically meaningful magnetic record of its history, it is essential that it contains magnetic minerals which are capable of carrying stable magnetic remanence. Of the natural occurring magnetic minerals, magnetite is the most important because of its abundance and strong magnetic signature. The stability, i.e., the resistance to demagnetisation or reorientation, of magnetic remanence is related to grain size; in smaller grains the magnetic moments align to have single domain (SD) structures, in larger grains complex magnetic patterns are formed (multidomain (MD)). “Classical” domain theory predicts that SD remanence is stable, whilst MD remanence is not. However experimental evidence has shown that both SD and MD grains can have stable remanences. In this thesis the origin of stable MD remanence is examined. There are two opposing theories; one suggests that the stability is due to independent SD-like structures, the other postulates that the stability is due to metastable MD structure. A series of experiments were designed to examine the stability using a selection of characterised synthetic and natural samples. Low-stress hydrothermal recrystallised samples where grown for this study. For the first time, the stability of thermoremanence induced in hydrothermal crystals to cooling was examined. The results agree with previous observations for crushed and natural magnetites, and support kinematic models. The behaviour of SIRM and thermoremanences in MD magnetite to low-temperature cooling to below the crystallographic Verwey transition at 120-124 K (T_v) and the cubic magnetocrystalline anisotropy isotropic point (T_k) at 130 K was investigated. On cooling through T_v, SIRM was observed to decrease and demagnetise, however thermoremanence was found to display a large increase in the magnetisation at T_v, which was partially re- versible on warming. The size of the anomaly is shown to be dependent on the temperature at which the thermoremanence is acquired, internal stress and grain size. The anomaly is attributed to the large increase in the magnetocrystalline anisotropy which occurs on cooling through T_v . It is postulated that low-temperature cycling demagnetisation is due to kinematic processes which occur on cooling between room temperature and T_k. Characterisation of low-temperature treated remanence and partially alternating field demagnetised remanence, suggest that the stable remanence is multidomain. Low-temperature cooling of remanence in single sub-micron crystals was simulated using micromagnetic models. The models predict the observed anomaly for thermoremanence on cooling through T_v, and also the relative behaviour of SIRM and thermoremanence. The single domain threshold was calculated for the low-temperature phase of magnetite, and was found to be 0.14 microns, compared to 0.07 microns at room temperature.

Subjects/Keywords: 538.7; Palaeomagnetism and rock magnetism; multi domain magnetite; Verwey transition; micro magnetic modelling; thermoremanence

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Muxworthy, A. R. (1998). Stability of magnetic remanence in multidomain magnetite. (Doctoral Dissertation). University of Oxford. Retrieved from http://ora.ox.ac.uk/objects/uuid:bc70e665-4c54-4ab5-98fa-d43ccecd07a1 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390505

Chicago Manual of Style (16^th Edition):

Muxworthy, Adrian R. “Stability of magnetic remanence in multidomain magnetite.” 1998. Doctoral Dissertation, University of Oxford. Accessed January 22, 2021. http://ora.ox.ac.uk/objects/uuid:bc70e665-4c54-4ab5-98fa-d43ccecd07a1 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390505.

MLA Handbook (7^th Edition):

Muxworthy, Adrian R. “Stability of magnetic remanence in multidomain magnetite.” 1998. Web. 22 Jan 2021.

Vancouver:

Muxworthy AR. Stability of magnetic remanence in multidomain magnetite. [Internet] [Doctoral dissertation]. University of Oxford; 1998. [cited 2021 Jan 22]. Available from: http://ora.ox.ac.uk/objects/uuid:bc70e665-4c54-4ab5-98fa-d43ccecd07a1 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390505.

Council of Science Editors:

Muxworthy AR. Stability of magnetic remanence in multidomain magnetite. [Doctoral Dissertation]. University of Oxford; 1998. Available from: http://ora.ox.ac.uk/objects/uuid:bc70e665-4c54-4ab5-98fa-d43ccecd07a1 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390505

University of Groningen

8. Kemperink, Maria Gesina. Van observatie tot extase. Sensitivische proza rond 1900.

Degree: Faculteit der Letteren, 1988, University of Groningen

URL: https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; 6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; 11370/6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; urn:isbn:9020422332 ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html

► A la fin du dix-neuvième siècle, un courant littéraire particulier apparait aux Pays-Bas: le Sensitivisme. Ce courant essaie, en amplifiant la perception des sens jusqu'à… (more)

Subjects/Keywords: Lodewijk Alberdingk Thijm, Albert Verwey (1865-1937); Lodewijk van Deyssel pseud. van Karel Joan; Proefschriften (vorm); Nederlands, Proza, Sensitivisme; 1900-1910; 1890-1900; Nederlandse letterkunde

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kemperink, M. G. (1988). Van observatie tot extase. Sensitivische proza rond 1900. (Doctoral Dissertation). University of Groningen. Retrieved from https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; 6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; 11370/6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; urn:isbn:9020422332 ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html

Chicago Manual of Style (16^th Edition):

Kemperink, Maria Gesina. “Van observatie tot extase. Sensitivische proza rond 1900.” 1988. Doctoral Dissertation, University of Groningen. Accessed January 22, 2021. https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; 6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; 11370/6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; urn:isbn:9020422332 ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html.

MLA Handbook (7^th Edition):

Kemperink, Maria Gesina. “Van observatie tot extase. Sensitivische proza rond 1900.” 1988. Web. 22 Jan 2021.

Vancouver:

Kemperink MG. Van observatie tot extase. Sensitivische proza rond 1900. [Internet] [Doctoral dissertation]. University of Groningen; 1988. [cited 2021 Jan 22]. Available from: https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; 6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; 11370/6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; urn:isbn:9020422332 ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html.

Council of Science Editors:

Kemperink MG. Van observatie tot extase. Sensitivische proza rond 1900. [Doctoral Dissertation]. University of Groningen; 1988. Available from: https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; 6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; 11370/6ed42e21-d48c-42c5-8fc4-305db37cbf5a ; urn:isbn:9020422332 ; urn:nbn:nl:ui:11-dbi/48e09a7c831c8 ; https://www.rug.nl/research/portal/en/publications/van-observatie-tot-extase-sensitivische-proza-rond-1900(6ed42e21-d48c-42c5-8fc4-305db37cbf5a).html

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations