+publisher:"University of Florida" +contributor:("BISWAS,AMLAN")

University of Florida

1. Grant, Daniel M. Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites.

Degree: PhD, Physics, 2015, University of Florida

► Perovskite manganese oxide "manganites" have attracted a large amount of research attention and show a wide variety of complex behaviors, including colossal responses to external… (more)

Subjects/Keywords: Anisotropy; Coercivity; Electric fields; Electric potential; Magnetic fields; Magnetism; Magnetization; Magnets; Photolithography; Thin films; coercive – dielectrophoresis – field – magnetism – manganite – microstructures – perovskite – phase – separation; City of Madison ( local )

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APA (6^th Edition):

Grant, D. M. (2015). Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0047728

Chicago Manual of Style (16^th Edition):

Grant, Daniel M. “Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites.” 2015. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0047728.

MLA Handbook (7^th Edition):

Grant, Daniel M. “Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites.” 2015. Web. 11 Apr 2021.

Vancouver:

Grant DM. Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites. [Internet] [Doctoral dissertation]. University of Florida; 2015. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0047728.

Council of Science Editors:

Grant DM. Effect of Electric Field and Strain on the Magnetic Properties of Phase Separated Manganites. [Doctoral Dissertation]. University of Florida; 2015. Available from: https://ufdc.ufl.edu/UFE0047728

University of Florida

2. Zou, Jie. Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems.

Degree: PhD, Physics, 2012, University of Florida

URL: https://ufdc.ufl.edu/UFE0044059

► Fluctuations are ubiquitous. It plays an important role in all physical and biological systems, including microelectromechanical systems (MEMS). Due to the relatively small size, MEMS… (more)

Subjects/Keywords: Electric potential; Electrodes; Electrostatics; Etching; Geometry; Microelectromechanical systems; Non Gaussianity; Oscillators; Signals; Silicon; casimir – fluctuations – mems – noise – on-chip

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APA (6^th Edition):

Zou, J. (2012). Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0044059

Chicago Manual of Style (16^th Edition):

Zou, Jie. “Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems.” 2012. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0044059.

MLA Handbook (7^th Edition):

Zou, Jie. “Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems.” 2012. Web. 11 Apr 2021.

Vancouver:

Zou J. Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems. [Internet] [Doctoral dissertation]. University of Florida; 2012. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0044059.

Council of Science Editors:

Zou J. Detecting Classical and Quantum Fluctuations with Microelectromechanical Systems. [Doctoral Dissertation]. University of Florida; 2012. Available from: https://ufdc.ufl.edu/UFE0044059

University of Florida

3. Buvaev, Sanal V. Magnetotransport Study of Disordered Thin Films.

Degree: PhD, Physics, 2014, University of Florida

URL: https://ufdc.ufl.edu/UFE0046226

► This work presents a magnetotransport study of disordered thin films and consists of two projects. The first project is a continuation of previous experience on… (more)

Subjects/Keywords: Bismuth; Conductivity; Electrons; Hall effect; Magnetic fields; Magnetism; Magnets; Magnons; Temperature dependence; Uniform Resource Locators; disordered – films – thin

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APA (6^th Edition):

Buvaev, S. V. (2014). Magnetotransport Study of Disordered Thin Films. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0046226

Chicago Manual of Style (16^th Edition):

Buvaev, Sanal V. “Magnetotransport Study of Disordered Thin Films.” 2014. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0046226.

MLA Handbook (7^th Edition):

Buvaev, Sanal V. “Magnetotransport Study of Disordered Thin Films.” 2014. Web. 11 Apr 2021.

Vancouver:

Buvaev SV. Magnetotransport Study of Disordered Thin Films. [Internet] [Doctoral dissertation]. University of Florida; 2014. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0046226.

Council of Science Editors:

Buvaev SV. Magnetotransport Study of Disordered Thin Films. [Doctoral Dissertation]. University of Florida; 2014. Available from: https://ufdc.ufl.edu/UFE0046226

University of Florida

4. Atallah, Pascale. Precision Polyolefins Additives for Extrusion Process.

Degree: PhD, Chemistry, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0046148

► Extrusion of polyethylene leads to defects, such as meltfracture and sharkskin roughness when performed at high rates and pressures.Silicones and fluorocarbons are known to act… (more)

▼ Extrusion of polyethylene leads to defects, such as meltfracture and sharkskin roughness when performed at high rates and pressures.Silicones and fluorocarbons are known to act as slippery agents, reducing thosedefects. Typical silicones and fluorocarbon additives present a number oftechnology disadvantages. Because of their nature, commercial silicones andfluorocarbons do not mix well with polyethylene. Consequently, they have been used to coat thedie of the extruder before the addition of polyethylene. This method is notefficient for large scale production, since it requires frequent interruptionof the process to recoat the die. The approach we envision eliminates theseproblems entirely. This dissertation describes the synthesis of novelextrusion aids for polyethylene using the precision branching technologydeveloped in the Wagener group. Precisely placed silicones and fluorinebranches of various branch lengths between precision long-run polyethylenesegments can be synthesized using Acyclic Diene Metathesis (ADMET). Thelong-run polyethylene segments between branches will allow for better mixing ofthe extrusion aid additive in the extruder, and equally important, the long runpolyethylene units between branches will co-crystallize with polyethylene afterexiting the extruder. This represents the first such application in extrusionaid technology. The purpose of this work is to identify successful syntheticmethods that will be used to produce extrusion aids in which the branch sizesand distances between branches can be varied. The goal is to find theappropriate polyethylene run length and branch size for optimum performance. At least three benefits accrue for these research results:1) the extrusion aid additive will be “locked” into the polymer (viaco-crystallization) leading a cleaner processing: 2) lower extrusion pressureswill be needed for the same output thus saving energy; 3) less die swell, meltfracture, and sharkskin effects will be observed, resulting in an improvedproduct. Very small amounts of the additive are needed to achieve all positiveeffects and low molecular weight polymers are enough to lead to positiveresults. ( en ) Advisors/Committee Members: WAGENER,KENNETH B (committee chair), APONICK,AARON (committee member), ENHOLM,JONATHAN E (committee member), BISWAS,AMLAN (committee member).

Subjects/Keywords: Alcohols; Catalysts; Chemicals; Monomers; Polyethylenes; Polymerization; Polymers; Silicones; Siloxanes; Solvents; additive – admet – extrusion – polyolefin – precision

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APA (6^th Edition):

Atallah, P. (2013). Precision Polyolefins Additives for Extrusion Process. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0046148

Chicago Manual of Style (16^th Edition):

Atallah, Pascale. “Precision Polyolefins Additives for Extrusion Process.” 2013. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0046148.

MLA Handbook (7^th Edition):

Atallah, Pascale. “Precision Polyolefins Additives for Extrusion Process.” 2013. Web. 11 Apr 2021.

Vancouver:

Atallah P. Precision Polyolefins Additives for Extrusion Process. [Internet] [Doctoral dissertation]. University of Florida; 2013. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0046148.

Council of Science Editors:

Atallah P. Precision Polyolefins Additives for Extrusion Process. [Doctoral Dissertation]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0046148

University of Florida

5. Uzakbaiuly, Berik. Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings.

Degree: PhD, Physics, 2016, University of Florida

URL: https://ufdc.ufl.edu/UFE0049916

► Silicon immersion gratings (SIGs) have offered a great deal of improvement in high resolution infrared spectroscopy used for astronomy. They offer a 3.4 times gain… (more)

Subjects/Keywords: Conductivity; Impurities; Light refraction; Moths; Reflectance; Silicon; Spectrometers; Transmittance; Vibration mode; Wavelengths; grating – immersion – impurity – silicon

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APA (6^th Edition):

Uzakbaiuly, B. (2016). Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0049916

Chicago Manual of Style (16^th Edition):

Uzakbaiuly, Berik. “Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings.” 2016. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0049916.

MLA Handbook (7^th Edition):

Uzakbaiuly, Berik. “Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings.” 2016. Web. 11 Apr 2021.

Vancouver:

Uzakbaiuly B. Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings. [Internet] [Doctoral dissertation]. University of Florida; 2016. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0049916.

Council of Science Editors:

Uzakbaiuly B. Infrared Spectroscopy of High Purity Silicon and Silicon Immersion Gratings. [Doctoral Dissertation]. University of Florida; 2016. Available from: https://ufdc.ufl.edu/UFE0049916

University of Florida

6. Ghosh, Siddhartha. Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films.

Degree: PhD, Physics, 2012, University of Florida

URL: https://ufdc.ufl.edu/UFE0044864

► Magnetic materials restricted in nano-scale gives rise to extremely fascinating behavior which is both important due to their potential applications as well as for their… (more)

Subjects/Keywords: Chromium; Conductivity; Electrons; Magnetic fields; Magnetism; Magnetization; Magnets; Superlattices; Temperature dependence; Thin films; physics

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APA (6^th Edition):

Ghosh, S. (2012). Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0044864

Chicago Manual of Style (16^th Edition):

Ghosh, Siddhartha. “Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films.” 2012. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0044864.

MLA Handbook (7^th Edition):

Ghosh, Siddhartha. “Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films.” 2012. Web. 11 Apr 2021.

Vancouver:

Ghosh S. Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films. [Internet] [Doctoral dissertation]. University of Florida; 2012. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0044864.

Council of Science Editors:

Ghosh S. Experimental Studies on Magnetic Nano Structures and Anti-Ferromagnetic Thin Films. [Doctoral Dissertation]. University of Florida; 2012. Available from: https://ufdc.ufl.edu/UFE0044864

University of Florida

7. Nasrollahi, Zahra. Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite.

Degree: PhD, Physics, 2014, University of Florida

URL: https://ufdc.ufl.edu/UFE0045420

► Electrochromic polymers (ECPs) exhibit reversible optical modulation in a wide spectral range as a function of an externally applied voltage. In this work, ECPs have… (more)

Subjects/Keywords: Charge carriers; Conductivity; Dielectric materials; Doping; Electronics; Electrons; Graphite; Polymers; Reflectance; Temperature dependence; electrochromic – polymer – transmissive

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APA (6^th Edition):

Nasrollahi, Z. (2014). Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045420

Chicago Manual of Style (16^th Edition):

Nasrollahi, Zahra. “Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite.” 2014. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0045420.

MLA Handbook (7^th Edition):

Nasrollahi, Zahra. “Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite.” 2014. Web. 11 Apr 2021.

Vancouver:

Nasrollahi Z. Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite. [Internet] [Doctoral dissertation]. University of Florida; 2014. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0045420.

Council of Science Editors:

Nasrollahi Z. Spectroscopoic Studies of Polymers in Transmissive/Absorptive Electrochromic Devices, and Doped Graphite. [Doctoral Dissertation]. University of Florida; 2014. Available from: https://ufdc.ufl.edu/UFE0045420

University of Florida

8. Dasbiswas, Kinjal. Defects in Novel Superfluids Supersolid Helium and Cold Gases.

Degree: PhD, Physics, 2012, University of Florida

URL: https://ufdc.ufl.edu/UFE0044532

► We investigate the role played by various topological defects, especially crystal dislocations and super?uid vortices, in some novel super?uids - such as the putative supersolid… (more)

Subjects/Keywords: Atoms; Eigenvalues; Energy; Grain boundaries; Ground state; Helium; Magnetic fields; Quantum tunneling; Superfluidity; Velocity; bec – dislocation – superfluid – supersolid – vortex

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APA (6^th Edition):

Dasbiswas, K. (2012). Defects in Novel Superfluids Supersolid Helium and Cold Gases. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0044532

Chicago Manual of Style (16^th Edition):

Dasbiswas, Kinjal. “Defects in Novel Superfluids Supersolid Helium and Cold Gases.” 2012. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0044532.

MLA Handbook (7^th Edition):

Dasbiswas, Kinjal. “Defects in Novel Superfluids Supersolid Helium and Cold Gases.” 2012. Web. 11 Apr 2021.

Vancouver:

Dasbiswas K. Defects in Novel Superfluids Supersolid Helium and Cold Gases. [Internet] [Doctoral dissertation]. University of Florida; 2012. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0044532.

Council of Science Editors:

Dasbiswas K. Defects in Novel Superfluids Supersolid Helium and Cold Gases. [Doctoral Dissertation]. University of Florida; 2012. Available from: https://ufdc.ufl.edu/UFE0044532

University of Florida

9. Petterson, Maureen K. Nanostructured Carbon Nanotube Schottky Junction Solar Cells.

Degree: PhD, Physics, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0045926

► Research on photovoltaic cells has been ongoing for numerous decades, yet only a few device structures have passed the test of affordability, longevity, and efficiency.… (more)

▼ Research on photovoltaic cells has been ongoing for numerous decades, yet only a few device structures have passed the test of affordability, longevity, and efficiency. Volatile markets, decreasing resources, and a penchant for innovation fuel the continued research of different architectures utilizing various organic and inorganic materials. Concomitant with an increase in solar cell efficiency is a deeper understanding of the underlying physical processes present in such devices, something which benefits all scientific fields. This dissertation explores and exploits the physical processes uncovered during experiments aimed at improving solar cells efficiency through surface texturing. Not only do our modifications increase device efficiency, but these advances can be implemented in other semiconductor based devices. Silicon nanowires have long been known for their excellent antireflection properties, but have suffered substantially from recombination at the surface, relegating them to academic and industrial research projects. Nonetheless, progress has been made in alleviating issues plaguing silicon nanowire devices. Here, we deposit a disperse carbon nanotube network on tops of silicon nanowires to produce a high performing solar cell. Previous experiments on carbon nanotube- silicon solar cells made use of an ionic liquid to modulate the nanotube Fermi level via electronic gating. This modulation changed the Schottky barrier height of the device and decreased the carbon nanotube film resistance, leading to power conversion efficiencies of up to 12% for a gate voltage of -0.75V. Further experiments uncovered an additional mechanism in which the ionic liquid induced and inversion layer within the silicon, greatly facilitating hole extraction by repelling electrons from the silicon surface (and consequently reducing recombination). We exploit this induced inversion layer within our silicon nanowire solar cells and show a greatly increased power conversion efficiency of over 15%, the highest reported efficiency for silicon nanowire based devices. We also investigate the physical and chemical processes responsible for degradation and subsequently use advanced passivation techniques to alleviate these losses. Specifically, deposition of aluminum oxide via atomic layer deposition creates a high quality, conformal, dielectric layer that inhibits electrochemical reactions between the ionic liquid and the silicon, leading to minimal reduction in performance as the gate voltage is applied. We also show that contamination of the ionic liquid with oxygen or water vapor reduced the electrochemical window, leading to redox reactions for gate voltages previously thought to be well within the electrochemical window. Controlling for these two degradation paths, we show stable performance of our electronically gated carbon nanotube on silicon solar cells. These improvements are not applicable only to our devices, but have implications for many liquid electrolyte devices, most notably the liquid junction cells research in the… Advisors/Committee Members: Rinzler, Andrew Gabriel (committee chair), Biswas, Amlan (committee member), Stanton, Christopher Jay (committee member), Tanner, David B (committee member), So, Franky Fat Kei (committee member).

Subjects/Keywords: Carbon nanotubes; Electric current; Electric potential; Graphene; Ionic liquids; Nanotubes; Nanowires; Photovoltaic cells; Semiconductors; Silicon; nanotubes – photovoltaics – schottky

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APA (6^th Edition):

Petterson, M. K. (2013). Nanostructured Carbon Nanotube Schottky Junction Solar Cells. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045926

Chicago Manual of Style (16^th Edition):

Petterson, Maureen K. “Nanostructured Carbon Nanotube Schottky Junction Solar Cells.” 2013. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0045926.

MLA Handbook (7^th Edition):

Petterson, Maureen K. “Nanostructured Carbon Nanotube Schottky Junction Solar Cells.” 2013. Web. 11 Apr 2021.

Vancouver:

Petterson MK. Nanostructured Carbon Nanotube Schottky Junction Solar Cells. [Internet] [Doctoral dissertation]. University of Florida; 2013. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0045926.

Council of Science Editors:

Petterson MK. Nanostructured Carbon Nanotube Schottky Junction Solar Cells. [Doctoral Dissertation]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0045926

University of Florida

10. Mhin, Sung Wook. Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films.

Degree: PhD, Materials Science and Engineering, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0045898

► Leadzirconate titanate (Pb(Zrx,Ti1-xO3, PZT) is awell-known piezoelectric and ferroelectric material. PZT in the form of thinfilms has current applications in capacitors, microsensors and microscalemechanical bugs.… (more)

▼ Leadzirconate titanate (Pb(Zrx,Ti1-xO3, PZT) is awell-known piezoelectric and ferroelectric material. PZT in the form of thinfilms has current applications in capacitors, microsensors and microscalemechanical bugs. For the preparation of PZT thin films, chemical solutiondeposition is one of the most utilized techniques due to the low cost andaccurate control of stoichiometry in the thin film. During chemical solutiondeposition, PZT precursor solutions are deposited onto a substrate using spincoating, and after pyrolysis, amorphous thin films are obtained. The amorphousthin films are crystallized by heating to a higher temperature. Intermediate PtxPband fluorite phases are commonly observed prior to the formation of perovskitePZT thin films during crystallization. In addition, depending on the differentprocessing conditions during crystallization such as the atmosphericconditions, heating rates and different substrates, different texture can beobtained in PZT thin films. However, the mechanism of texture control in PZTthin films is not well understood, because it is difficult to track the changesduring fast crystallization from amorphous to perovskite PZT within a fewseconds. Thus, in situ x-raydiffraction (XRD) measurements are useful to observe the phase and textureevolution of PZT thin films during crystallization. Inthis dissertation, in situmeasurements of PZT thin films using laboratory- and synchrotron based XRD wereconducted to investigate the phase and texture evolution duringcrystallization. The stability of intermediate phases and perovskite PZT wasobserved during crystallization in different atmospheric conditions. Based onthese observations, a novel processing method was developed. Switching atmospheric conditions during crystallization ofPZT thin films suppressed the intermetallic PtxPb phase and promotedthe perovskite PZT phase. Further,based on the observations of phase and texture evolution using differentheating rates and substrates during crystallization, a mechanism for texturecontrol of PZT thin films is provided. 111 texture was observed in PZT on 111Pt electrodes. It is suggested that 111 Pt nucleates 111PZT directly. Similar trends for the formation of 111 texture were observedin PZT on an amorphized PbTiO3 (PTO) seed layer, which implies thatnucleation of 111 texture occurred on a 111 Pt electrode. Conversely,dominant 100 texture was observed in PZT on amorphized PTO duringcrystallization at slow heating rates. It is suggested that surface orhomogeneous nucleation occurs at slow heating rates to promote 100texture in PTO layer at low temperature, and 100 textured PZT isnucleated from 100 texture of PTO layer at higher temperature. Also,interdiffusion between the PTO layer and the PZT layer during crystallizationled to the formation of PZT with an inhomogeneous composition throughout thethin films. Unlike PZT on amorphized PTO, dominant 100 texture was observedin PZT on crystalline PTO regardless of heating rates during crystallization.Also, the formation of the PZT thin films was observed… Advisors/Committee Members: Jones, Jacob L (committee chair), Phillpot, Simon R (committee member), Myers, Michele V (committee member), Perry, Scott S (committee member), Biswas, Amlan (committee member).

Subjects/Keywords: Crystallization; Electrodes; Fluorite; Heating; Nucleation; Parent teacher organizations; Perovskites; Pyrolysis; Thin films; Wave diffraction; crystallization – pzt – thinfilms – xrd

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APA (6^th Edition):

Mhin, S. W. (2013). Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045898

Chicago Manual of Style (16^th Edition):

Mhin, Sung Wook. “Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films.” 2013. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0045898.

MLA Handbook (7^th Edition):

Mhin, Sung Wook. “Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films.” 2013. Web. 11 Apr 2021.

Vancouver:

Mhin SW. Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films. [Internet] [Doctoral dissertation]. University of Florida; 2013. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0045898.

Council of Science Editors:

Mhin SW. Crystallization Behavior of Solution Deposited Lead Zirconate Titanate Thin Films. [Doctoral Dissertation]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0045898

University of Florida

11. Miller, Kevin H. Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides.

Degree: PhD, Physics, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0045238

► The contents of this thesis report the characterization of novel complex-oxide single crystals that are candidates for the discovery of new multiferroic materials and the… (more)

Subjects/Keywords: Conceptual lattices; Crystals; Dielectric materials; Electric fields; Magnetic fields; Magnetism; Magnets; Oscillators; Phonons; Reflectance; magnons – multiferroic

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APA (6^th Edition):

Miller, K. H. (2013). Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045238

Chicago Manual of Style (16^th Edition):

Miller, Kevin H. “Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides.” 2013. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0045238.

MLA Handbook (7^th Edition):

Miller, Kevin H. “Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides.” 2013. Web. 11 Apr 2021.

Vancouver:

Miller KH. Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides. [Internet] [Doctoral dissertation]. University of Florida; 2013. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0045238.

Council of Science Editors:

Miller KH. Infrared Study of Magnetic and Electric Excitations in Novel Complex Oxides. [Doctoral Dissertation]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0045238

University of Florida

12. Timmerwilke, John M. Point Contact Studies of Iron Based Superconductors.

Degree: PhD, Physics, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0045403

► This work presents spectroscopic measurements on Cobalt doped Barium Iron Arsenide at different dopings. The technique used is Point-Contact Spectroscopy, PCS. This technique is well… (more)

Subjects/Keywords: Anisotropy; Crystals; Doping; Electric potential; Electrons; Spectroscopy; Superconductivity; Superconductors; Symmetry; Uniform Resource Locators; iron-based – point-contact – superconductivity

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APA (6^th Edition):

Timmerwilke, J. M. (2013). Point Contact Studies of Iron Based Superconductors. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045403

Chicago Manual of Style (16^th Edition):

Timmerwilke, John M. “Point Contact Studies of Iron Based Superconductors.” 2013. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0045403.

MLA Handbook (7^th Edition):

Timmerwilke, John M. “Point Contact Studies of Iron Based Superconductors.” 2013. Web. 11 Apr 2021.

Vancouver:

Timmerwilke JM. Point Contact Studies of Iron Based Superconductors. [Internet] [Doctoral dissertation]. University of Florida; 2013. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0045403.

Council of Science Editors:

Timmerwilke JM. Point Contact Studies of Iron Based Superconductors. [Doctoral Dissertation]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0045403

University of Florida

13. Lu, Zhichao. Physical Analysis and Design of Nanoscale Floating-Body Dram Cells.

Degree: PhD, Electrical and Computer Engineering, 2010, University of Florida

URL: https://ufdc.ufl.edu/UFE0042135

► This dissertation addresses physical analysis and design issues of nanoscale floating-body cells (FBC), which are also known as capacitorless dynamic random-access memory(DRAM) cells. A novel… (more)

▼ This dissertation addresses physical analysis and design issues of nanoscale floating-body cells (FBC), which are also known as capacitorless dynamic random-access memory(DRAM) cells. A novel two-transistor floating-body/gate cell (FBGC), and upgraded versions of it, are proposed and experimentally demonstrated. As the conventional one-transistor and one-capacitor (1T/1C) DRAM technology is aggressively scaled, novel device structures and materials have to be introduced to meet International Technology Roadmap for Semiconductors (ITRS) performance requirements. Novel device structures and materials bring a lot of processing and integration challenges to current complementary metal-oxide-semiconductor (CMOS) technology. To avoid these challenges, capacitorless DRAM, which is based on silicon-on-insulator (SOI) CMOS including partially depleted (PD) and fully depleted (FD) MOS transistors (MOSFETs), is attracting a lot of interest. This technology, which uses the floating body of the SOI MOSFET as the storage element, can potentially replace the conventional 1T/1C DRAM cell in the near future. The basic working principle of the FBC is to utilize the floating-body effect inherent in the PD/SOI MOSFET; the FD/SOI MOSFET also shows the floating-body effect when the substrate, or back gate is biased for accumulation. However, the physical explanation of the floating-body effect in the FD/SOI device is not clear. Based on numerical simulations, physical insights are gained on the effect and on FBC performance, e.g., the sense margin. Relying on the physical insights of the floating-body effects, a novel two-transistor(2T) FBC is proposed. By using the first transistor?s (T1) body to directly drive the second transistor?s gate, the 2T FBC eliminates the body-factor limitation on the sense margin. The memory performance is demonstrated with the University of Florida physics-based compact double-gate MOSFET model (UFDG). The predicted results show that the common impact ionization-based write method produces too much power dissipation. To resolve this problem, the 2T-FBC is refined to Ver. 1 of the floating-body/gate cell(FBGC1). The major feature of FBGC1 is the source tied source to the drain in T1. To improve the manufacturability of FBGC1, Ver. 2 (FBGC2) is proposed, which in essence is a gated diode (T1) plus a conventional transistor (T2). Gate-induced drain leakage (GIDL)current is used to write ?1? in FBGC2. The performance is demonstrated by 90nm FinFET technology and also by numerical simulation. One issue with FBGC2 is the short retention time with bit-line (BL) disturbs. Hence Ver. 3 (FBGC3) is proposed to the resolve this problem. Unlike FBGC2 which accumulates the channel to get GIDL charging current, FBGC3 inverts the channel and introduces tunneling current at the source side for charging, thereby separating the charging mechanisms for write and hold. By optimizing the device structure, FBGC3 demonstrates ~10s retention time with worst-case disturb. To make FBGC3 operate faster, Ver. 4 (FBGC4) is proposed. In… Advisors/Committee Members: Fossum, Jerry G. (committee chair), Guo, Jing (committee member), Fox, Robert M. (committee member), Biswas, Amlan (committee member).

Subjects/Keywords: Academic achievement; Capacitance; Cells; Drains; DRAM; Electric current; Electric potential; Signals; Simulations; Transistors; capacitorlessdram, doublegatefinfet, floatingbodycell, floatingbodyeffects, gidl, soimosfet; City of Gainesville ( local )

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APA (6^th Edition):

Lu, Z. (2010). Physical Analysis and Design of Nanoscale Floating-Body Dram Cells. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0042135

Chicago Manual of Style (16^th Edition):

Lu, Zhichao. “Physical Analysis and Design of Nanoscale Floating-Body Dram Cells.” 2010. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0042135.

MLA Handbook (7^th Edition):

Lu, Zhichao. “Physical Analysis and Design of Nanoscale Floating-Body Dram Cells.” 2010. Web. 11 Apr 2021.

Vancouver:

Lu Z. Physical Analysis and Design of Nanoscale Floating-Body Dram Cells. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0042135.

Council of Science Editors:

Lu Z. Physical Analysis and Design of Nanoscale Floating-Body Dram Cells. [Doctoral Dissertation]. University of Florida; 2010. Available from: https://ufdc.ufl.edu/UFE0042135

University of Florida

14. Baure, George, Jr. Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases.

Degree: PhD, Materials Science and Engineering, 2016, University of Florida

URL: https://ufdc.ufl.edu/UFE0050368

The theme of this dissertation is utilizing impedance spectroscopy to illuminate Advisors/Committee Members: NINO,JUAN C (committee chair), SIGMUND,WOLFGANG MICHAEL (committee member), PERRY,SCOTT S (committee member), BISWAS,AMLAN (committee member).

Subjects/Keywords: Activation energy; Conductivity; Electric fields; Electrodes; Electrolytes; Grain boundaries; Intermetallics; Ion currents; Sapphire; Thin films; boundary – cells – ceria – crystal – doped – electrical – epitaxial – ferroelectric – fib – film – fuel – gallium – grain – impedance – intermetallic – lead – neodymia – oxide – phases – properties – secondary – silver – single – solid – spectroscopy – telluride – thin – titanate – zirconate

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APA (6^th Edition):

Baure, George, J. (2016). Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0050368

Chicago Manual of Style (16^th Edition):

Baure, George, Jr. “Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases.” 2016. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0050368.

MLA Handbook (7^th Edition):

Baure, George, Jr. “Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases.” 2016. Web. 11 Apr 2021.

Vancouver:

Baure, George J. Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases. [Internet] [Doctoral dissertation]. University of Florida; 2016. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0050368.

Council of Science Editors:

Baure, George J. Electrical Performance of Functional Thin Films Effect of Grain Boundaries and Secondary Phases. [Doctoral Dissertation]. University of Florida; 2016. Available from: https://ufdc.ufl.edu/UFE0050368

University of Florida

15. Hou, Jie. Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices.

Degree: PhD, Physics, 2017, University of Florida

URL: https://ufdc.ufl.edu/UFE0051871

Subjects/Keywords: avalanche; cnt; fet; schottkyjunction; solarcell

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APA (6^th Edition):

Hou, J. (2017). Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0051871

Chicago Manual of Style (16^th Edition):

Hou, Jie. “Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices.” 2017. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0051871.

MLA Handbook (7^th Edition):

Hou, Jie. “Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices.” 2017. Web. 11 Apr 2021.

Vancouver:

Hou J. Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices. [Internet] [Doctoral dissertation]. University of Florida; 2017. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0051871.

Council of Science Editors:

Hou J. Gate Modulated Carbon Nanotube Silicon Schottky Junction Devices. [Doctoral Dissertation]. University of Florida; 2017. Available from: https://ufdc.ufl.edu/UFE0051871

University of Florida

16. Zheng, Pan. Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices.

Degree: PhD, Physics, 2016, University of Florida

URL: https://ufdc.ufl.edu/UFE0049284

Subjects/Keywords: 3he; cryogenics; devices; fluid; mems; nonlinear; quantum; states; superfluid; surface

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APA (6^th Edition):

Zheng, P. (2016). Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0049284

Chicago Manual of Style (16^th Edition):

Zheng, Pan. “Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices.” 2016. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0049284.

MLA Handbook (7^th Edition):

Zheng, Pan. “Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices.” 2016. Web. 11 Apr 2021.

Vancouver:

Zheng P. Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices. [Internet] [Doctoral dissertation]. University of Florida; 2016. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0049284.

Council of Science Editors:

Zheng P. Study of Normal and Superfluid 3He Films with Micro-electro-mechanical Devices. [Doctoral Dissertation]. University of Florida; 2016. Available from: https://ufdc.ufl.edu/UFE0049284

University of Florida

17. Quintero Cabra, Pedro A. Magnetic and Electrical-Transport Studies of Molecule-Based Magnets.

Degree: PhD, Physics, 2015, University of Florida

URL: https://ufdc.ufl.edu/UFE0049004

Molecule-based magnets are prime candidates for multifunctional devices due Advisors/Committee Members: MEISEL,MARK W (committee chair), INGERSENT,J KEVIN (committee member), BISWAS,AMLAN (committee member), TALHAM,DANIEL R (committee member).

Subjects/Keywords: Anisotropy; Capacitance; Eggshells; Hysteresis; Low temperature; Magnetic fields; Magnetism; Magnets; Nanoparticles; Transition temperature; core-shell – ctist – heterostructure – magnetic-anisotropy – magnetoelastic – molecule-based-magnet – pba – photomagnetism

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APA (6^th Edition):

Quintero Cabra, P. A. (2015). Magnetic and Electrical-Transport Studies of Molecule-Based Magnets. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0049004

Chicago Manual of Style (16^th Edition):

Quintero Cabra, Pedro A. “Magnetic and Electrical-Transport Studies of Molecule-Based Magnets.” 2015. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0049004.

MLA Handbook (7^th Edition):

Quintero Cabra, Pedro A. “Magnetic and Electrical-Transport Studies of Molecule-Based Magnets.” 2015. Web. 11 Apr 2021.

Vancouver:

Quintero Cabra PA. Magnetic and Electrical-Transport Studies of Molecule-Based Magnets. [Internet] [Doctoral dissertation]. University of Florida; 2015. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0049004.

Council of Science Editors:

Quintero Cabra PA. Magnetic and Electrical-Transport Studies of Molecule-Based Magnets. [Doctoral Dissertation]. University of Florida; 2015. Available from: https://ufdc.ufl.edu/UFE0049004

University of Florida

18. Kwak, In Hae. Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films.

Degree: PhD, Physics, 2016, University of Florida

URL: https://ufdc.ufl.edu/UFE0050353

Subjects/Keywords: films; lsmo; manganites; phase; separation; step; strain; ultrathin

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APA (6^th Edition):

Kwak, I. H. (2016). Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0050353

Chicago Manual of Style (16^th Edition):

Kwak, In Hae. “Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films.” 2016. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0050353.

MLA Handbook (7^th Edition):

Kwak, In Hae. “Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films.” 2016. Web. 11 Apr 2021.

Vancouver:

Kwak IH. Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films. [Internet] [Doctoral dissertation]. University of Florida; 2016. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0050353.

Council of Science Editors:

Kwak IH. Phase Separation in Strained La0.67Sr0.33MnO3 Thin Films. [Doctoral Dissertation]. University of Florida; 2016. Available from: https://ufdc.ufl.edu/UFE0050353

University of Florida

19. Mickel,Patrick R. 'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides.

Degree: PhD, Physics, 2011, University of Florida

URL: https://ufdc.ufl.edu/UFE0043236

► This thesis has focused on the electronic and magnetic properties of thin-film oxide crystals. Oxides are home to some of the richest physics in condensed… (more)

Subjects/Keywords: Capacitance; Conceptual lattices; Dielectric materials; Electric fields; Electrical phases; Magnetic fields; Magnetism; Magnetization; Magnets; Orbitals; dielectric – film – magnetodielectric – magnetoelectric – manganite – multiferroic – phase – soft – strain – thermodynamics – thin

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APA (6^th Edition):

R, M. (2011). 'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0043236

Chicago Manual of Style (16^th Edition):

R, Mickel,Patrick. “'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides.” 2011. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0043236.

MLA Handbook (7^th Edition):

R, Mickel,Patrick. “'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides.” 2011. Web. 11 Apr 2021.

Vancouver:

R M. 'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides. [Internet] [Doctoral dissertation]. University of Florida; 2011. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0043236.

Council of Science Editors:

R M. 'Soft Electronic Matter', Magnetoelectric Coupling, and Multiferroism in Complex Oxides. [Doctoral Dissertation]. University of Florida; 2011. Available from: https://ufdc.ufl.edu/UFE0043236

University of Florida

20. Jeen,Hyoung Jeen. Magnetoelectric Effects in Manganites.

Degree: PhD, Physics, 2011, University of Florida

URL: https://ufdc.ufl.edu/UFE0042870

► Research on manganites has been conducted for more than half century. Recent discoveries of colossal responses to external fields such as colossal magnetoresistance effects and… (more)

▼ Research on manganites has been conducted for more than half century. Recent discoveries of colossal responses to external fields such as colossal magnetoresistance effects and correlation among spin, orbital, and lattice in phase separated manganites and multiferroic manganites have motivated me to understand these materials. The main purpose of this dissertation is to understand magnetoelectric effects in phase separated (La_1-yPr_y)_1-xCa_xMnO₃ (LPCMO) thin films and multiferroic BiMnO₃ (BMO) thin films. First, high quality phase separated manganite thin films have been successfully grown. To grow the high quality manganite thin films, extensive effort was devoted to fine tuning of oxygen pressure, temperature, and laser fluence during film growth. As-grown films were characterized with various ex-situ techniques: magnetization measurements, transport measurements, x-ray diffraction, atomic force microscopy, and/or transmission electron microscopy to remove the effects of impurities and unwanted strains except substrate induced strain. Second, three major results were obtained in high quality phase separated LPCMO thin films. These results are based on the dynamic nature of phases in LPCMO. 1) LPCMO thin films showed single domain to multi-domain transition during cooling. This transition can be tuned by substrate stress induced in-plane magnetic anisotropy. 2) Evidence for the origin of colossal electroresistance (CER) effect has been observed. The CER is triggered by dielectrophoresis, or movements of ferromagnetic metallic (FMM) phase, which is manifested in anisotropic transport properties in microfabricated LPCMO cross structures. This fluidic nature of the FMM phase in LPCMO under high electric fields lead to exotic magnetoelectric effects. 3) Electric field effects on magnetotransport properties have been observed. This phenomena can also be tuned by the combined effect of substrate strain and current flow. This combined effect of electric and magnetic fields and strain at the interface of LPCMO suggest new ways to control magnetism (magnetotransport) with electric fields. Third, impurity-free and epitaxial BMO thin films were grown. These films showed ferromagnetism and ferroelectricity at low temperature. Magnetoelectric effects are discussed, especially magnetization change due to electric fields. ( en ) Advisors/Committee Members: Biswas, Amlan (committee chair), Dorsey, Alan T (committee member), Lee, Yoonseok (committee member), Hebard, Arthur F (committee member), Norton, David P (committee member).

Subjects/Keywords: Anisotropy; Electric fields; Ions; Magnetic fields; Magnetism; Magnetization; Magnets; Nonprofit organizations; Oxygen; Thin films; cer – cmr – magnetoelectric – manganites – multiferroics – pld

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APA (6^th Edition):

Jeen, J. (2011). Magnetoelectric Effects in Manganites. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0042870

Chicago Manual of Style (16^th Edition):

Jeen, Jeen,Hyoung. “Magnetoelectric Effects in Manganites.” 2011. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0042870.

MLA Handbook (7^th Edition):

Jeen, Jeen,Hyoung. “Magnetoelectric Effects in Manganites.” 2011. Web. 11 Apr 2021.

Vancouver:

Jeen J. Magnetoelectric Effects in Manganites. [Internet] [Doctoral dissertation]. University of Florida; 2011. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0042870.

Council of Science Editors:

Jeen J. Magnetoelectric Effects in Manganites. [Doctoral Dissertation]. University of Florida; 2011. Available from: https://ufdc.ufl.edu/UFE0042870

University of Florida

21. Singh, Guneeta. Size Effects in Phase Separated Manganite Nanostructures.

Degree: PhD, Physics, 2009, University of Florida

URL: https://ufdc.ufl.edu/UFE0024399

► Size Effects in Phase Separated Manganite Nanostructures This work describes a detailed nanometer scale experimental study of a phenomenon known as phase separation, in a… (more)

▼ Size Effects in Phase Separated Manganite Nanostructures This work describes a detailed nanometer scale experimental study of a phenomenon known as phase separation, in a class of ceramic materials know as the manganites. The manganite (La,Pr,Ca)MnO3 was chosen for the studies due to the micrometer scale phase separation in this particular material. In (La,Pr,Ca)MnO3 phase separation is electronic, magnetic and structural in nature, and occurs within a small window of temperatures. Within this temperature range the sample becomes electronically `texturized' in that the sample is no longer homogeneously insulating or conducting, even though the physical chemistry and properties of the sample remain constant. It contains a mix of both insulating and conducting properties within well defined spatial regions. The regions are on the order of a micrometer. The conducting regions are ferromagnetic and have a psuedo cubic (orthorhombic but very nearly cubic) atomic structure while the insulating regions are anitiferromagnetic with an orthorhombic, distorted structure. To understand the physics of the individual phase separated regions a technique was developed for fabricating narrow (La,Pr,Ca)MnO3 wires (in the shape of bridges) of nanometer width such that during the phase separated temperature range, one or a few phase separated regions form along the length of the wire. This has allowed transport measurements across a discrete number of phase separated regions giving physical insights into the nature of the individual regions and the boundaries between them. In this way, it is possible to identify several distinct physical mechanisms that act simultaneously on the nanometer scale giving rise to the unusual properties observed in bulk or unpatterned thin film samples. Transport measurements across the narrow bridges as a function of temperature and magnetic field revealed evidence of alternating insulating and metallic regions spanning the bridge width, aligned along the length of the bridge. First, evidence of direct electron tunneling between two or more ferromagnetic metallic (FM) regions separated by antiferromagnetic insulating (AFI) regions was observed. Magnetoresistance measurements reveal that often, the ferromagnetic metallic regions have different coercive fields (possibly due to varying sizes) which affect the tunnel probabilities (i.e. the probability decreases when the spins are anti-aligned). This gives rise to large and sharp low field peaks when resistance is measured as a function of magnetic field – the classical signature of tunneling magnetoresistance (TMR). Further, signatures of an exchange bias which gives rise to asymmetric TMR peaks were also identified in the measurements. These two phenomenon can help explain anomalous low field magnetoresistance observed in bulk and unpatterned thin film samples. The data also reveal that at temperatures below the phase separated temperature range, when the unpatterned thin film samples are nearly fully ferromagnetic metallic, the narrow bridges in contrast… Advisors/Committee Members: Hebard, Arthur F. (committee chair), Biswas, Amlan (committee member), Hirschfeld, Peter J. (committee member), Tanner, David B. (committee member), Nino, Juan C. (committee member).

Subjects/Keywords: Capacitance; Electric current; Electric fields; Electrical phases; Magnetic fields; Magnetism; Magnets; Orbitals; Thin films; Transition temperature; bias, blockade, colossal, coulomb, domain, electroresistance, exchange, film, insulating, intrinsic, laprcamno, magnetiresistance, magnetoresistance, manganite, nano, nanofabrication, nanostructures, perovskite, phase, polarization, separation, simmons, spin, stripe, thin, tunneling, wall

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

APA (6^th Edition):

Singh, G. (2009). Size Effects in Phase Separated Manganite Nanostructures. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0024399

Chicago Manual of Style (16^th Edition):

Singh, Guneeta. “Size Effects in Phase Separated Manganite Nanostructures.” 2009. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0024399.

MLA Handbook (7^th Edition):

Singh, Guneeta. “Size Effects in Phase Separated Manganite Nanostructures.” 2009. Web. 11 Apr 2021.

Vancouver:

Singh G. Size Effects in Phase Separated Manganite Nanostructures. [Internet] [Doctoral dissertation]. University of Florida; 2009. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0024399.

Council of Science Editors:

Singh G. Size Effects in Phase Separated Manganite Nanostructures. [Doctoral Dissertation]. University of Florida; 2009. Available from: https://ufdc.ufl.edu/UFE0024399

University of Florida

22. Liu, Bo. Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives.

Degree: PhD, Physics, 2010, University of Florida

URL: https://ufdc.ufl.edu/UFE0042342

► A carbon nanotube enabled vertical field effect transistor (CN-VFET) utilizes a dilute carbon nanotube (CNT) random network as the source electrode, and features a stack… (more)

▼ A carbon nanotube enabled vertical field effect transistor (CN-VFET) utilizes a dilute carbon nanotube (CNT) random network as the source electrode, and features a stack gate-dielectric-source-channel-drain structure as opposed to the lateral channel between the source and drain structure found in a conventional organic thin film transistor. The structural and electronic properties of the single wall carbon nanotubes help to fully unlock the potential of this new device architecture. The high aspect ratio of the CNTs allows a percolating random network to be made easily with open areas between the CNTs that the electric field can penetrate without much penalty on the conductivity. The low density of states of the CNTs permits the electric field tuning of their Fermi level, while their well passivated surface inhibit covalent bond formation that can cause Fermi level pinning, leaving the barrier height predisposed to gate field modulation. By adding an electroluminescent layer and modifying the top contact to allow electron injection, a carbon nanotube enabled vertical organic light emitting transistor (CN-VOLET) is demonstrated. The luminance is controlled by the gate field which modulates the source-drain current by modulating the hole injection barrier at the CNT source electrode. Such gate control should permit new pixel drive schemes and affords the potential for increased device lifetimes. Returning to the base CN-VFET a non-volatile memory element is realized by adding a charge storage layer on top of the dielectric. The memory element demonstrates a large, fully gate sweep programmable, hysteresis in the cyclic transfer curves exhibiting on/off ratios > 4 orders of magnitude. The carbon nanotube random network source electrode facilitates charge injection into the charge storage layer, realizing the strong memory effect without sacrificing mobility in the vertical channel. Given their intrinsically simple fabrication and compact size CN-VFETs could provide a path to cost-effective, high density organic memory devices. By utilizing a blend of p-type and n-type organic semiconductors as the channel material an ambipolar CN-VFET is demonstrated. By the virtue of their short channel lengths (without the need for high resolution patterning) the organic blend, ambipolar CN-VFET has important potential advantages that are discussed. Inverters based on ambipolar CN-VFETs are demonstrated. In contrast to inverters made from lateral channel ambipolar transistors, inverters made using the ambipolar CN-VFETs exhibit low leakage currents due to a diode-like transport characteristic in the devices. ( en ) Advisors/Committee Members: Rinzler, Andrew G. (committee chair), Biswas, Amlan (committee member), Hershfield, Selman P. (committee member), Hebard, Arthur F. (committee member), So, Franky (committee member).

Subjects/Keywords: Carbon nanotubes; Dielectric materials; Drains; Electric current; Electric potential; Electrodes; Field effect transistors; Inverters; Nanotubes; Transistors

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APA (6^th Edition):

Liu, B. (2010). Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0042342

Chicago Manual of Style (16^th Edition):

Liu, Bo. “Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives.” 2010. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0042342.

MLA Handbook (7^th Edition):

Liu, Bo. “Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives.” 2010. Web. 11 Apr 2021.

Vancouver:

Liu B. Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0042342.

Council of Science Editors:

Liu B. Carbon Nanotube Enabled Vertical Field Effect Transistors and Their Device Derivatives. [Doctoral Dissertation]. University of Florida; 2010. Available from: https://ufdc.ufl.edu/UFE0042342

University of Florida

23. Tongay, Sefaattin. Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes.

Degree: PhD, Physics, 2010, University of Florida

URL: https://ufdc.ufl.edu/UFE0041457

► The goal of this dissertation is to incorporate graphite and graphene into today's semiconductor technology as a Schottky barrier diodes (metal / semiconductor junctions) that… (more)

▼ The goal of this dissertation is to incorporate graphite and graphene into today's semiconductor technology as a Schottky barrier diodes (metal / semiconductor junctions) that are widely used in metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), high temperature and frequency devices, solar cells and sensors/detectors. The first part of the dissertation aims to give the reader a general idea about the physics at the metal-semiconductor junctions and essential theory background. The second chapter of the dissertation questions effects of temperature and magnetic field on the diode characteristics of Schottky junctions. In this chapter, we present observation of negative magnetocapacitance on GaAs:Si/Au junctions and fully equipped with the theory, we present a phenomenological explanation for the observed effect. In the third chapter, we for the first time introduce multi-layer-graphene as a metal (semimetal) electrode to form Schottky barriers on various technologically significant semiconductors such as Si, GaAs, SiC and GaN. Multi-layer-graphene/ semiconductor junctions not only display good current-voltage (I-V) and capacitance-voltage (C-V) characteristics but also are significant since the Schottky barrier height and characteristics are mainly governed by the interaction and bond formation at few layers on the metal and semiconductor interface. This automatically implies that the presented results also hold for graphene/semiconductor junctions. Chapter 4, takes the Schottky formation at the multi-layer-graphene(graphene)/ semiconductor junction to another level and aims to change the Fermi level of the metal electrode by intercalation with Bromine and tune the barrier height. Observed results are significant in MESFET technology since different barrier height are desired depending on the application. The remainder of the dissertation, focuses on the properties of graphite and graphene to have more understanding about the content presented in the previous chapters. Chapter 5, gives a brief theory background about graphite and graphene while chapter 6 and chapter 7 discuss electrical properties of graphite at high temperatures where it starts to decouple from each graphene layer and acts as bi-layer graphene and with bromine intercation where there is c-axis lattice constant expansion and each graphene plane becomes more isolated. Chapter 8, gives a detailed description about epitaxial graphene growth in SiC by joule annealing technique, and we end the chapter with future directions. ( en ) Advisors/Committee Members: Hebard, Arthur F. (committee chair), Rinzler, Andrew G. (committee member), Biswas, Amlan (committee member), Maslov, Dmitrii (committee member), Pearton, Stephen J. (committee member).

Subjects/Keywords: Atoms; Bromine; Carbon; Electrical resistivity; Electrons; Graphene; Graphite; Room temperature; Semiconductors; Temperature dependence; carbon, condensed, device, electronic, gallium, gan, graphene, graphite, hemts, hightemperature, intercalation, magnetization, magnetodielectric, mesfet, mosfet, optical, quantum, schottky, semiconductors, silicon

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APA (6^th Edition):

Tongay, S. (2010). Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0041457

Chicago Manual of Style (16^th Edition):

Tongay, Sefaattin. “Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes.” 2010. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0041457.

MLA Handbook (7^th Edition):

Tongay, Sefaattin. “Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes.” 2010. Web. 11 Apr 2021.

Vancouver:

Tongay S. Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0041457.

Council of Science Editors:

Tongay S. Graphite-Graphene Semiconductor Junctions and Magneto-Dielectric Coupling in Schottky Diodes. [Doctoral Dissertation]. University of Florida; 2010. Available from: https://ufdc.ufl.edu/UFE0041457

University of Florida

24. Verma,Prakash. Increasing the Applicability of Density Functional Theory.

Degree: PhD, Chemistry, 2011, University of Florida

URL: https://ufdc.ufl.edu/UFE0042848

► According to density functional theory(DFT), the density is a sufficient variable for the description of degenerate or non-degenerate ground state of molecules. The density is… (more)

Subjects/Keywords: Approximation; Density functional theory; Eigenvalues; Electrons; Energy; Flux density; Ion density; Ionization; Orbitals; Particle density; bartlett – dft – non – oep – rpa

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APA (6^th Edition):

Verma,Prakash. (2011). Increasing the Applicability of Density Functional Theory. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0042848

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

Verma,Prakash. “Increasing the Applicability of Density Functional Theory.” 2011. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0042848.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

Verma,Prakash. “Increasing the Applicability of Density Functional Theory.” 2011. Web. 11 Apr 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

Verma,Prakash. Increasing the Applicability of Density Functional Theory. [Internet] [Doctoral dissertation]. University of Florida; 2011. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0042848.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

Verma,Prakash. Increasing the Applicability of Density Functional Theory. [Doctoral Dissertation]. University of Florida; 2011. Available from: https://ufdc.ufl.edu/UFE0042848

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

University of Florida

25. Moon, Byoung. Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound.

Degree: PhD, Physics, 2010, University of Florida

URL: https://ufdc.ufl.edu/UFE0041531

► STUDY ON THE EFFECTS OF ANISOTROPIC DISORDER ON SUPERFLUID HELIUM THREE IN HIGH POROSITY AEROGEL USING LONGITUDINAL ULTRASOUND Longitudinal sound attenuation measurements in superfluid 3He… (more)

Subjects/Keywords: Acoustic attenuation; Aerogels; Audio frequencies; Impurities; Liquids; Magnetic fields; Phase diagrams; Temperature dependence; Transducers; Transition temperature; aerogel, attenuation, gapless, helium, longitudinal, phase, pvdf, superfluid, ultrasound

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APA (6^th Edition):

Moon, B. (2010). Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0041531

Chicago Manual of Style (16^th Edition):

Moon, Byoung. “Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound.” 2010. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0041531.

MLA Handbook (7^th Edition):

Moon, Byoung. “Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound.” 2010. Web. 11 Apr 2021.

Vancouver:

Moon B. Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0041531.

Council of Science Editors:

Moon B. Study on the Effects of Anisotropic Disorder on Superfluid Helium Three in High Porosity Aerogel Using Longitudinal Ultrasound. [Doctoral Dissertation]. University of Florida; 2010. Available from: https://ufdc.ufl.edu/UFE0041531

University of Florida

26. Davies, Ryan. Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications.

Degree: PhD, Materials Science and Engineering, 2009, University of Florida

URL: https://ufdc.ufl.edu/UFE0041092

► ION IMPLANTATION OF GADOLINIUM IN COMPOUND SEMICONDUCTOR MATERIALS AND POTENTIAL SPINTRONIC DEVICE APPLICATIONS As device dimensions have continued to shrink, atomistic scale fluctuations in material… (more)

▼ ION IMPLANTATION OF GADOLINIUM IN COMPOUND SEMICONDUCTOR MATERIALS AND POTENTIAL SPINTRONIC DEVICE APPLICATIONS As device dimensions have continued to shrink, atomistic scale fluctuations in material properties are beginning to limit continued improvements in device performance. Various technologies are being pursued to overcome this problem. Spin transport electronics, or spintronics, has been proposed as an attractive approach. This technology utilizes the spin of the electron, in addition to the charge of the electron, to transmit information through a device. The most promising materials for spintronic device applications are dilute magnetic semiconductors, which are formed when dilute amounts of magnetic atoms are incorporated into semiconductor materials. Recently, ion implantation has been studied as the incorporation method of magnetic ions into a host semiconductor material system for potential spintronic applications. This method provides excellent control over the quantity of the implanted ion and the resultant magnetic properties of the implanted material. For this study, the compound semiconductor materials GaN, ZnO, and GaAs are examined as target materials for Gd ion implantation. Before implantation, these materials exhibited ferromagnetic behavior without the known presence of magnetic impurities and with a dependence on the applied magnetic field/sample surface orientation. Measuring the magnetic properties of these materials with a perpendicular orientation between the applied field and the sample surface exhibited a larger magnetic signal than examining with a parallel orientation between the applied field and sample surface, described in this work as an anisotropic enhancement effect. Ferromagnetism was demonstrated in hysteresis loops visible at both low temperature (10 K) and room temperature. The ferromagnetic mechanism occurring in the non-implanted materials is speculated as being due to anion-related defects (vacancies and interstitials). Ferromagnetism was also demonstrated in the implanted compound semiconductor materials. Implanting Gd ions into GaN has resulted in this material exhibiting ferromagnetic behavior before any thermal annealing treatment. Co-implanting Si ions with Gd ions in GaN also shows room temperature ferromagnetism and a larger magnetic moment than the same GaN only implanted with Gd. Additional studies into the effects of Gd ion implantation on the magnetic properties of another wurtzite crystal structure compound semiconductor material (ZnO) and a small band gap semiconductor material (GaAs) provide additional insight into the ferromagnetic mechanism present in these materials. The mechanism occurring in the implanted materials is speculated as being due to interactions between the native defects and defects introduced during implantation with the implanted Gd. This interaction may be caused by long-range spin polarization that is demonstrated by the large magnetic moments observed in this work. Anion-related defects (vacancies and interstitials) appear to be the… Advisors/Committee Members: Abernathy, Cammy R. (committee chair), Gila, Brent P. (committee member), Norton, David P. (committee member), Pearton, Stephen J. (committee member), Biswas, Amlan (committee member).

Subjects/Keywords: Atoms; Dosage; Ferromagnetism; Ions; Magnetic fields; Magnetism; Magnetization; Magnets; Room temperature; Semiconductors; gaas, gan, gd, implantation, ion, magnetic, semiconductor, spintronics, zno

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

APA (6^th Edition):

Davies, R. (2009). Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0041092

Chicago Manual of Style (16^th Edition):

Davies, Ryan. “Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications.” 2009. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0041092.

MLA Handbook (7^th Edition):

Davies, Ryan. “Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications.” 2009. Web. 11 Apr 2021.

Vancouver:

Davies R. Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications. [Internet] [Doctoral dissertation]. University of Florida; 2009. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0041092.

Council of Science Editors:

Davies R. Ion Implantation of Gadolinium in Compound Semiconductor Materials and Potential Spintronic Device Applications. [Doctoral Dissertation]. University of Florida; 2009. Available from: https://ufdc.ufl.edu/UFE0041092

University of Florida

27. Yun, Sung. Effect of Disorder in Cuprates and Manganites.

Degree: PhD, Physics, 2008, University of Florida

URL: https://ufdc.ufl.edu/UFE0022312

► This dissertation is an inquiry into the characteristics of two representative transition metal oxides, cuprates and manganites. The pairing mechanism of cuprates is not yet… (more)

▼ This dissertation is an inquiry into the characteristics of two representative transition metal oxides, cuprates and manganites. The pairing mechanism of cuprates is not yet fully understood. The origin of the normal state gap (a unique feature of high Tc superconductors) needs to be ruminated in various ways to understand its relation to the superconducting gap. We have performed point contact spectroscopy experiments using junctions between a normal metal (Pt-Rh) and electron-doped Pr2-xCexCuO4 (PCCO) films and single crystals. To probe the normal state at low temperatures (T =1.5 K), the superconductivity was suppressed by applying high magnetic fields (up to 31 T). From this experiment, we could infer that the normal state gap may not be he 'pseudogap,' instead it originates from the presence of disorder in the complex transition metal oxide. Due to the comparable energies of co-existing phases, manganites exhibit unique dependencies on a variety of external parameters such as light, x-rays, mechanical strain, magnetic field and electric field. These properties not only demonstrate its importance in physics as a strongly correlated system but also mark the potential of this material for practical applications. We studied properties of phase separated hole-doped manganite thin films of (La1-yPry) 0.67Ca0.33MnO3 grown on (110) NdGaO3 substrates using pulsed laser deposition (PLD). First, we found a giant positive magnetoresistance of about 30% at magnetic fields less than 1 T in ultra-thin films (7.5 nm) of (La0.5Pr0.5)0.67Ca0.33MnO3 . Second, we were able to control the magnetic phase with an electric field in the out-of-plane direction using a specially designed nano-fabricated double layered structure with two different compositions of manganite, (La0.4Pr0.6)0.67Ca0.33MnO3 and La0.67Ca0.33MnO3. Last, we have studied the effect of strain and disorder on the phase-separated state in thin films of (La1-yPry) 0.67Ca0.33MnO3 (LPCMO, y = 0.4, 0.5, 0.6). Our observations show that a small amount of strain (~10^-4) can move the phase boundaries in the fluid phase separated (FPS) state. A reduction of the piezoresistance in the ion-bombarded samples suggests that such extrinsic disorder can pin the phase boundaries and reduce the fluidity of the FPS state. ( en ) Advisors/Committee Members: Biswas, Amlan (committee chair), Hirschfeld, Peter J. (committee member), Tanner, David B. (committee member), Hill, Stephen O. (committee member), Norton, David P. (committee member).

Subjects/Keywords: Cuprates; Electric fields; Electric potential; Electrical phases; Low temperature; Magnetic fields; Magnetism; Magnets; Temperature dependence; Thin films; disorder, high, manganites, phase, pseudogap, strain, transition

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

APA (6^th Edition):

Yun, S. (2008). Effect of Disorder in Cuprates and Manganites. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0022312

Chicago Manual of Style (16^th Edition):

Yun, Sung. “Effect of Disorder in Cuprates and Manganites.” 2008. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0022312.

MLA Handbook (7^th Edition):

Yun, Sung. “Effect of Disorder in Cuprates and Manganites.” 2008. Web. 11 Apr 2021.

Vancouver:

Yun S. Effect of Disorder in Cuprates and Manganites. [Internet] [Doctoral dissertation]. University of Florida; 2008. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0022312.

Council of Science Editors:

Yun S. Effect of Disorder in Cuprates and Manganites. [Doctoral Dissertation]. University of Florida; 2008. Available from: https://ufdc.ufl.edu/UFE0022312

University of Florida

28. Bhupathi, Pradeep. Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels.

Degree: PhD, Physics, 2009, University of Florida

URL: https://ufdc.ufl.edu/UFE0024389

► An ultra low temperature cryostat is designed and implemented in this work to perform experiments at sub-millikelvin temperatures, specifically aimed at understanding the superfluid phases… (more)

▼ An ultra low temperature cryostat is designed and implemented in this work to perform experiments at sub-millikelvin temperatures, specifically aimed at understanding the superfluid phases of Helium-3 in various scenarios. The cryostat is a combination of a dilution refrigerator (Oxford Kelvinox 400) with a base temperature of 5.2 mK and a 48 mole copper block as the adiabatic nuclear demagnetization stage with a lowest temperature of about 200 microK. With the various techniques implemented for limiting the ambient heat leak to the cryostat, we were able to stay below 1 mK for longer than 5 weeks. The details of design, construction and performance of the cryostat are presented. We measured high frequency shear acoustic impedance in superfluid Helium-3 in 98% porosity aerogel at pressures of 29 bar and 32 bar in magnetic fields upto 3 kG with the aerogel cylinder compressed along the symmetry axis to generate global anisotropy. With 5% compression, there is an indication of a supercooled A-like to B-like transition in aerogel in a wider temperature width than the A phase in the bulk, while at 10% axial compression, the A-like to B-like transition is absent on cooling down to 300 microK in zero magnetic field and in magnetic fields up to 3 kG. This behavior is in contrast to that in Helium-3 in uncompressed aerogels, in which the supercooled A-like to B-like transitions have been identified by various experimental techniques. Our result is consistent with theoretical predictions. To characterize the anisotropy in compressed aerogels, optical birefringence is measured in 98% porosity silica aerogel samples subjected to various degrees of uniaxial compression up to 15% strain, with wavelengths between 200 to 800 nm. Uncompressed aerogels exhibit no or a minimal degree of birefringence, indicating the isotropic nature of the material over the length scale of the wavelength. Uniaxial compression of aerogel introduces global anisotropy, which produces birefringence in the material. We observed a quasi-linear strain dependence in Delta n = n_e - n_o in compressed aerogels, where n_e(o) is the index of refraction for the extraordinary (ordinary) ray of light that has its polarization parallel to the compression axis. Incidentally, this effect has potential applications for aerogels as tunable waveplates operating in a broad spectral range. ( en ) Advisors/Committee Members: Lee, Yoonseok (committee chair), Kumar, Pradeep P. (committee member), Meisel, Mark W. (committee member), Biswas, Amlan (committee member), Scott, Michael J. (committee member).

Subjects/Keywords: Aerogels; Cooling; Cryostats; Heating; Liquids; Low temperature; Magnetic fields; Magnetism; Pumps; Transmittance; aerogels, bhupathi, birefringence, cryostat, helium, spectroscopy, superfluid, ultrasound

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

APA (6^th Edition):

Bhupathi, P. (2009). Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0024389

Chicago Manual of Style (16^th Edition):

Bhupathi, Pradeep. “Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels.” 2009. Doctoral Dissertation, University of Florida. Accessed April 11, 2021. https://ufdc.ufl.edu/UFE0024389.

MLA Handbook (7^th Edition):

Bhupathi, Pradeep. “Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels.” 2009. Web. 11 Apr 2021.

Vancouver:

Bhupathi P. Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels. [Internet] [Doctoral dissertation]. University of Florida; 2009. [cited 2021 Apr 11]. Available from: https://ufdc.ufl.edu/UFE0024389.

Council of Science Editors:

Bhupathi P. Construction of an Ultralow Temperature Cryostat and Transverse Acoustic Spectroscopy in Superfluid Helium-3 in Compressed Aerogels. [Doctoral Dissertation]. University of Florida; 2009. Available from: https://ufdc.ufl.edu/UFE0024389

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