• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 24
  • 4
  • 4
  • 1
  • Tagged with
  • 31
  • 31
  • 31
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Steric effects in the metallic-mirror to transparent-insulator transition in YHx

Messina, Troy Christopher 28 August 2008 (has links)
Not available / text
2

Steric effects in the metallic-mirror to transparent-insulator transition in YHx

Messina, Troy Christopher. January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.
3

Thermodynamics of metal-insulator systems

Kasl, Charles. January 1996 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. / The properties-of systems which undergo a metal-insulator (MI) transition are currently being extensively studied. Both the transport and thermodynamic properties of these MI systems show interesting behaviour, particularly near the MI transition. A complete theory to describe MI systems does not yet exist. In the present work the focus is on the thermodynamic properties of MI systems, in particular on the specific heat and susceptibility. The thermodynamic properties in the absence of a magnetic field are now well understood, with models such as the two-fluid model giving a good account of the behaviour. In finite magnetic fields the thermodynamic properties are even more interesting and varied. It is the aim of the present work to develop and test models to explain the effects of applying magnetic fields to MI systems. The focus is mainly on phosphorous doped silicon, and the results are gratifying. The theory should, however, also apply to other similar MI systems. / Andrew Chakane 2018
4

Numerical studies of a generalized double exchange model =: 廣義雙交換模型的數值硏究. / 廣義雙交換模型的數值硏究 / Numerical studies of a generalized double exchange model =: Guang yi shuang jiao huan mo xing de shu zhi yan jiu. / Guang yi shuang jiao huan mo xing de shu zhi yan jiu

January 1999 (has links)
Wong Chung Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 93-94). / Text in English; abstracts in English and Chinese. / Wong Chung Ki. / Abstract --- p.i / Acknowledgement --- p.iii / Contents --- p.iv / List of Figures --- p.viii / List of Tables --- p.xii / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Double exchange model --- p.3 / Chapter 1.3 --- This project --- p.5 / Chapter Chapter 2. --- The generalized double exchange model --- p.6 / Chapter 2.1 --- Assumptions of the model --- p.6 / Chapter 2.2 --- Transfer process of the mobile electrons --- p.7 / Chapter 2.3 --- Double exchange model --- p.9 / Chapter 2.4 --- The generalized double exchange model --- p.10 / Chapter 2.5 --- Previous results on the model --- p.13 / Chapter 2.5.1 --- Solution for two localized spins --- p.13 / Chapter 2.5.2 --- Ground state configuration for one doping electron and the electron concentration at half fill --- p.13 / Chapter 2.5.3 --- The planar spiral state and the canted ferromagnetic state --- p.14 / Chapter Chapter 3. --- Ground state calculations --- p.16 / Chapter 3.1 --- Minimization of ground state energy --- p.17 / Chapter 3.2 --- Energy and spin configuration --- p.18 / Chapter 3.3 --- Occupation number of mobile electrons --- p.19 / Chapter 3.4 --- Rotated occupation number of mobile electrons --- p.19 / Chapter Chapter 4. --- One-dimensional ground state results --- p.21 / Chapter 4.1 --- Zero superexchange coupling --- p.21 / Chapter 4.1.1 --- Total energy of the system --- p.21 / Chapter 4.1.2 --- Spin configuration and nearest neighbor spin-spin correlation --- p.23 / Chapter 4.1.3 --- Occupation number --- p.29 / Chapter 4.2 --- Antiferromagnetic superexchange coupling --- p.34 / Chapter 4.2.1 --- Total energy of the system --- p.35 / Chapter 4.2.2 --- Spin configuration and nearest neighbor spin-spin correlation --- p.36 / Chapter 4.2.3 --- Occupation number --- p.39 / Chapter 4.3 --- Discussions on the one-dimensional results --- p.43 / Chapter Chapter 5. --- Two-dimensional ground state results --- p.46 / Chapter 5.1 --- Zero superexchange coupling --- p.46 / Chapter 5.1.1 --- Total energy of the system --- p.46 / Chapter 5.1.2 --- Localized spin configuration --- p.47 / Chapter 5.1.3 --- Occupation number --- p.51 / Chapter 5.2 --- Nonzero superexchange coupling --- p.54 / Chapter 5.2.1 --- Total energy of the system --- p.54 / Chapter 5.2.2 --- Spin configuration --- p.54 / Chapter 5.2.3 --- Occupation number --- p.57 / Chapter 5.3 --- Discussions --- p.59 / Chapter Chapter 6. --- Finite temperature calculations on the model --- p.62 / Chapter 6.1 --- Quantum Monte Carlo simulation --- p.62 / Chapter 6.2 --- Heat capacity and magnetic susceptibility --- p.63 / Chapter 6.3 --- Localized spin-spin correlation --- p.64 / Chapter Chapter 7. --- Results at finite temperature --- p.65 / Chapter 7.1 --- Two-dimensional results without superexchange interaction --- p.65 / Chapter 7.1.1 --- Fourier transform of the spin-spin correlation --- p.65 / Chapter 7.1.2 --- Occupation number --- p.68 / Chapter 7.2 --- Two-dimensional results with nonzero superexchange interaction --- p.73 / Chapter 7.2.1 --- Fourier transform of the spin-spin correlation --- p.73 / Chapter 7.2.2 --- Occupation number --- p.74 / Chapter 7.3 --- Three-dimensional results with anisotropic exchange interaction --- p.77 / Chapter 7.3.1 --- Fourier transform of the spin-spin correlation --- p.77 / Chapter 7.3.2 --- Occupation number --- p.79 / Chapter 7.3.3 --- Magnetization --- p.81 / Chapter 7.3.4 --- Heat capacity --- p.81 / Chapter 7.3.5 --- Magnetic susceptibility --- p.82 / Chapter 7.3.6 --- Discussions --- p.83 / Chapter Chapter 8. --- Conclusions --- p.85 / Chapter Appendix A. --- Details on Euler rotation of the localized spin --- p.87 / Chapter Appendix B. --- Details on the calculation of the occupation number --- p.89 / Chapter B.1 --- Occupation number --- p.89 / Chapter B.2 --- Rotated occupation number --- p.90 / Chapter Appendix C. --- Fourier transform of the spin-spin correlation at T≠0 --- p.92 / Bibliography
5

Electrical properties of random metal-insulator composite near the percolation threshold /

Chen, In-Gann January 1987 (has links)
No description available.
6

Metal-insulator transition in boron-ion implanted type IIa diamond.

Tshepe, Tshakane January 2000 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy. / High purity natural type Il a diamond specimens were used in this study. Conducting layers in the surfaces of these diamonds were generated using low-ion dose multiple implantation-annealing steps. The implantation energies and the ion-doses were spread evenly to intermix the point-defects, thereby increasing the probability of interstitialvacancy recombinations and promoting dopant-interstitial-vacancy combination resulting in activated dopant sites in the implanted layers. The process used to prepare our samples is known as cold-implantation-rapid-annealing (CIRA). Carbon-ion and boron-ion implantation was used to prepare the diamond specimens, and de-conductivity measurements in the temperature range of 1.5-300 K were made following each CIRA sequence. An electrical conductivity crossover from the Mott variable range hopping (VRH) to the Efros-Shklovskii VRH conduction was observed when the temperature of insulating samples was lowered. The conductivity crossover temperature Tcross decreases with increasing concentration of the boron-ion dose in the implanted layers, indicating the narrowing of the Coulomb gap in the single-particle density of states near the Fermi energy. (Abbreviation abstract) / Andrew Chakane 2019
7

Epitaxial growth of La-Ca-Mn-O thin films with ultra-sharp metal-insulator transition =: 外延生長金屬--絶緣轉變非常明顯的La-Ca-Mn-薄膜. / 外延生長金屬--絶緣轉變非常明顯的La-Ca-Mn-O薄膜 / Epitaxial growth of La-Ca-Mn-O thin films with ultra-sharp metal-insulator transition =: Wai yan sheng chang jin shu--jue yuan zhuan bian fei chang ming xian de La-Ca-Mn-O bo mo. / Wai yan sheng chang jin shu--jue yuan zhuan bian fei chang ming xian de La-Ca-Mn-O bo mo

January 1999 (has links)
by Leung Chi Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Leung Chi Hung. / Acknowledgments --- p.i / Abstract --- p.ii-iii / Table of Contents --- p.iv-v / Figures Caption --- p.vi-xii / Tables Caption --- p.xiii / Chapter 1. --- Introduction / Chapter 1.1 --- "Magnetoresistance (MR),Giant Magnetoresistance (GMR),Colossal Magnetoresistance (CMR) and Their Applications" --- p.1-1 / Chapter 1.2 --- Colossalmagnetoresistance Effect in LCMO --- p.1-5 / Chapter 1.3 --- Significance of Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Film --- p.1-12 / Chapter 1.4 --- The Use of Silver in the YBCO --- p.1-14 / Chapter 1.5 --- Previews --- p.1-15 / Chapter 1.6 --- References --- p.1-17 / Chapter 2. --- Epitixial Growth of Single-Crystal LCMO Thin Film by FTS method / Chapter 2.1 --- Facing-Target Sputtering Method --- p.2-1 / Chapter 2.2 --- Fabrication of LCMO Targets --- p.2-4 / Chapter 2.3 --- Deposition of the LCMO Thin Film / Chapter 2.3.1 --- Deposition Condition --- p.2-6 / Chapter 2.3.2 --- Deposition Process --- p.2-9 / Chapter 2.4 --- X-ray Diffraction Studies and Surface Morphology --- p.2-11 / Chapter 2.5 --- M-S Transition of LCMO Thm Film --- p.2-15 / Chapter 2.6 --- Discussions --- p.2-19 / Chapter 3. --- The Role of Silver in LCMO / Chapter 3.1 --- Reaction between Ag and LCMO --- p.3-1 / Chapter 3.2 --- Grain Size and Transition Temperature in Bulk LCMO --- p.3-9 / Chapter 3.3 --- Improving the Sharpness of Metal - Semiconductor Transition and Crystallinity of LCMO Film --- p.3-15 / Chapter 3.4 --- Stabilization of the LCMO Structure --- p.3-21 / Chapter 3.5 --- Discussions --- p.3-25 / Chapter 4 --- Epitaxial Growth of the Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Film / Chapter 4.1 --- Synthesis Process of the Ultra-Sharp Metal-Semiconductor Transition LCMO Thin Films --- p.4-1 / Chapter 4.2 --- Resistivity and Magnetoresistance --- p.4-6 / Chapter 4.3 --- Thermal Annealing Effects / Chapter 4.3.1 --- Oxygen Annealing Effect --- p.4-15 / Chapter 4.3.1 --- High Pressure Annealing Effect --- p.4-20 / Chapter 4.3.2 --- Vacuum Annealing Effect --- p.4-23 / Chapter 4.4 --- Surface Morphology and Characterization --- p.4-27 / Chapter 4.5 --- Discussions --- p.4-37
8

Enhanced magnetoresistance in La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃ superlattices with ultra-sharp metal-insulator transition =: 金屬-絶緣轉變非常明顯的La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃超晶格薄膜的磁致電阻增强現象. / 金屬-絶緣轉變非常明顯的La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃超晶格薄膜的磁致電阻增强現象 / Enhanced magnetoresistance in La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃ superlattices with ultra-sharp metal-insulator transition =: Jin shu--jue yuan zhuan bian fei chang ming xian de La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃ chao jing ge bo mo de ci zhi dian zu zeng qiang xian xiang. / Jin shu--jue yuan zhuan bian fei chang ming xian de La₀.₆₇Ca₀.₃₃MnO₃/Pr₀.₆₇Ca₀.₃₃MnO₃ chao jing ge bo mo de ci zhi dian zu zeng qiang xian xiang

January 2002 (has links)
by Lo Wai Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Lo Wai Hung. / Acknowledgements --- p.1 / Abstract / 論文摘要 --- p.ii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.viii / Chapter Chapter 1. --- Introduction / Chapter 1.1. --- Magnetoresistance --- p.1 -1 / Chapter 1.1.1. --- Giant magnetoresistance (GMR) --- p.1 -2 / Chapter 1.1.2. --- Colossal Magnetoresistace (CMR) --- p.1 -2 / Chapter 1.2. --- Doping effects in La1-xCaxMn03 --- p.1-4 / Chapter 1.3. --- Metal-Insulator transition in CMR materials --- p.1 -8 / Chapter 1.3.1. --- The sharpness in Metal-Insulator transition --- p.1 -9 / Chapter 1.3.2. --- Possible model to explain CMR in rare-earth manganites --- p.1-12 / Chapter 1.4. --- Low field magnetoresistance --- p.1-14 / Chapter 1.4.1.1. --- Single crystal and polycrystalline perovskite manganites --- p.1-14 / Chapter 1.4.1.2. --- Manganite trilayer junctions --- p.1-15 / Chapter 1.4.2. --- Possible mechanism of low field MR --- p.1-16 / Chapter 1.5. --- Our motivation --- p.1-17 / Chapter 1.5.1. --- Brief review of several manganite superlattices systems --- p.1-18 / Chapter 1.5.2. --- Scope of this thesis work --- p.1-20 / References --- p.1-21 / Chapter Chapter 2. --- Epitaxial growth of LCMO thin films / Chapter 2.1. --- Deposition techniques --- p.2-1 / Chapter 2.1.1. --- Induction --- p.2-1 / Chapter 2.1.2. --- Facing-target sputtering (FTS) --- p.2-1 / Chapter 2.1.3. --- Vacuum system --- p.2-3 / Chapter 2.2. --- Fabrication and characterization of LCMO and PCMO targets --- p.2-4 / Chapter 2.3. --- Epitaxial growth of LCMO thin films --- p.2-9 / Chapter 2.3.1. --- Substrate materials --- p.2-9 / Chapter 2.3.2 --- Deposition --- p.2-10 / Chapter 2.3.2.1. --- Sample preparation --- p.2-10 / Chapter 2.3.2.2. --- Deposition procedure --- p.2-10 / Chapter 2.3.2.3. --- Inter-target distance --- p.2-11 / Chapter 2.3.2.4. --- Deposition Rate --- p.2-15 / Chapter 2.4. --- Substrate temperature effect --- p.2-17 / Chapter 2.4.1. --- Crystal Structure --- p.2-17 / Chapter 2.4.2. --- Transport properties --- p.2-20 / Chapter 2.4.2.1. --- Sharpness of M-I transport properties --- p.2-24 / Chapter 2.4.2.2. --- Magnetoresistance of LCMO/NGO films --- p.2-27 / Chapter 2.5. --- Thickness of LCMO thin film --- p.2-28 / Chapter 2.5.1. --- Crystal Structure --- p.2-29 / Chapter 2.5.2. --- M-I transition properties --- p.2-31 / Chapter 2.5.2.1. --- Sharpness of M-I transport properties --- p.2-35 / Chapter 2.5.2.2. --- Magnetoresistance of LCMO/NGO films --- p.2-36 / Chapter 2.5.2.3. --- Surface Morphology --- p.2-38 / Chapter 2.6. --- Epitaxial growth of PCMO thin films --- p.2-40 / Chapter 2.7. --- Conclusion --- p.2-42 / References --- p.2-43 / Chapter Chapter 3. --- LCMO/PCMO superlattices --- p.3-1 / Chapter 3.1. --- Variation of the PCMO thickness in LCMO/PCMO superlattices --- p.3-2 / Chapter 3.1.1. --- Sample Preparation --- p.3-2 / Chapter 3.1.2. --- Structure characterization by XRD --- p.3-3 / Chapter 3.1.3. --- Transport properties --- p.3-10 / Chapter 3.1.3.1. --- Sharpness of M-I transport properties --- p.3-14 / Chapter 3.1.3.2. --- Magnetoresistance of LCMO/PCMO superlattices --- p.3-16 / Chapter 3.2. --- Variation of the number of LCMO/PCMO bilayer --- p.3-19 / Chapter 3.2.1. --- Sample Preparation --- p.3-19 / Chapter 3.2.2. --- Structure characterization by XRD --- p.3-21 / Chapter 3.2.3. --- Transport properties --- p.3-23 / Chapter 3.2.3.1. --- Sharpness of M-I transport properties --- p.3-27 / Chapter 3.2.3.2. --- Magnetoresistance of LCMO/PCMO superlattices --- p.3-28 / Chapter 3.3. --- Fine adjusting the thickness of PCMO around 10Ain LCMO/PCMO superlattices / Chapter 3.3.1. --- Sample Preparation --- p.3-31 / Chapter 3.3.2. --- Characterization ofLCMO/PCMO superlattices by XRD --- p.3-32 / Chapter 3.3.3. --- Transport properties --- p.3-35 / Chapter 3.3.3.1. --- Sharpness of M-I transport properties --- p.3-39 / Chapter 3.3.3.2. --- Magnetoresistance of LCMO/PCMO superlattices --- p.3-41 / Chapter 3.4. --- Conclusion --- p.3-43 / References --- p.3-44 / Chapter Chapter 4. --- Low-field magnetoresistance (LFMR) / Chapter 4.1. --- Low-field magnetoresistance --- p.4-1 / Chapter 4.2. --- Conclusion --- p.4-5 / References --- p.4-6 / Chapter Chapter 5. --- Structure characterization of LCMO/PCMO superlatticess by crater edge profiling --- p.5-1 / Chapter 5.1. --- Sample preparation --- p.5-2 / Chapter 5.2. --- Structure Characterization --- p.5-2 / Chapter 5.2.1. --- X-ray diffraction (XRD) --- p.5-2 / Chapter 5.2.2. --- The crater edge profiling --- p.5-5 / Chapter 5.2.2.1. --- SEM --- p.5-5 / Chapter 5.2.2.2. --- AES line scan --- p.5-10 / Chapter 5.3. --- Crater edge profiling of P1OO/STO --- p.5-12 / Chapter 5.4. --- Conclusion --- p.5-15 / References --- p.5-16 / Chapter Chapter 6. --- Conclusion --- p.6-1
9

Metal-insulator transition in a switchable mirror /

Roy, Arunabha Shasanka. January 2001 (has links)
Thesis (Ph. D.)--University of Chicago, Department of Physics, 2001. / Includes bibliographical references. Also available on the Internet.
10

Metal-semiconductor transitions in nanoscale vanadium dioxide thin films, subwavelength holes, and nanoparticles /

Donev, Eugenii U. January 2008 (has links)
Thesis (Ph. D. in Physics)--Vanderbilt University, Dec. 2008. / Title from title screen. Includes bibliographical references.

Page generated in 0.0885 seconds