Synthesis and characterization of the iron-based superconductor: fluorine and yttrium co-doped SmFeAsO.

• Other Authors: Lai, Kwing To.
• Format: Others
• Language: English; Chinese
• Published: 2011
• Subjects: Organofluorine compounds > Synthesis; Yttrium alloys; Iron-based superconductors
• Online Access: http://library.cuhk.edu.hk/record=b5894795; http://repository.lib.cuhk.edu.hk/en/item/cuhk-327470

Lai, Kwing To = 鐵基超導體的合成與分析 : 氟及釔合摻SmFeAsO / 黎烱韜. === Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. === Includes bibliographical references. === Abstracts in English and Chinese. === Lai, Kwing To = Tie ji chao dao ti de he cheng yu fen xi : fu ji yi he shan SmFeAsO / Li Jiongtao. === Abstract --- p.i === 摘要 --- p.iii === Acknowledgements --- p.v === Table of contents --- p.vii === List of table captions --- p.x === List of figure captions --- p.xi === Chapter Chapter 1 --- Introduction --- p.1 === Chapter 1.1 --- Superconductivity --- p.1 === Chapter 1.1.1 --- Physical properties --- p.3 === Chapter 1.1.1.1 --- Zero resistance --- p.3 === Chapter 1.1.1.2 --- Meissner effect --- p.4 === Chapter 1.1.1.3 --- Josephson effect --- p.5 === Chapter 1.1.2 --- Type I and II superconductivity --- p.7 === Chapter 1.2 --- Iron-based superconductors --- p.7 === Chapter 1.2.1 --- Classifications and structures --- p.8 === Chapter 1.2.2 --- Physical properties --- p.12 === Chapter 1.2.3 --- Iron-based superconductors versus Cuprate superconductors --- p.13 === Chapter 1.2.4 --- Correlation between high-Tc superconductivity and magnetism --- p.14 === Chapter 1.2.5 --- Quantum phase transition by doping --- p.16 === Chapter 1.2.6 --- Sample preparation of undoped and doped iron-based superconductors --- p.17 === Chapter 1.3 --- Objectives of this research project --- p.18 === References --- p.20 === Chapter Chapter 2 --- Literature Review --- p.22 === Chapter 2.1 --- Theories of superconductivity --- p.22 === Chapter 2.1.1 --- London equation --- p.22 === Chapter 2.1.2 --- Ginzburg-Landau theory --- p.24 === Chapter 2.1.2.1 --- Mean-field theory and Landau theory --- p.24 === Chapter 2.1.2.2 --- Spatial varying order parameter and Gauge symmetry --- p.27 === Chapter 2.1.2.3 --- Applications --- p.31 === Chapter 2.1.3 --- BCS theory --- p.35 === Chapter 2.2 --- Magnetism in condensed matters --- p.39 === Chapter 2.2.1 --- Ferromagnetism and Antiferromagnetism from local moments --- p.40 === Chapter 2.2.1.1 --- Mathematical explanation in the mean-field approach --- p.40 === Chapter 2.2.1.2 --- Exchange interaction --- p.43 === Chapter 2.2.2 --- Antiferromagnetism in magnetic metals: Spin density wave --- p.45 === References --- p.52 === Chapter Chapter 3 --- Methodology and Instrumentation --- p.53 === Chapter 3.1 --- Sample preparation --- p.53 === Chapter 3.2 --- Characterization --- p.55 === Chapter 3.2.1 --- Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX) --- p.55 === Chapter 3.2.2 --- Transmission electron microscopy (TEM) and Electron diffraction --- p.55 === Chapter 3.2.3 --- X-ray diffraction (XRD) --- p.56 === Chapter 3.2.4 --- X-ray photoelectron spectroscopy (XPS) --- p.57 === Chapter 3.2.5 --- Physical properties measuring system (PPMS) --- p.58 === Chapter 3.2.5.1 --- Transport properties --- p.58 === Chapter 3.2.5.2 --- Magnetic properties --- p.60 === Chapter 3.2.6 --- Raman spectroscopy --- p.62 === Chapter 3.3 --- Precautions --- p.62 === References --- p.63 === Chapter Chapter 4 --- Results --- p.64 === Chapter 4.1 --- Fluorine-doped SmFeAsO --- p.64 === Chapter 4.1.1 --- Morphologies and microstructures --- p.67 === Chapter 4.1.2 --- Phase and composition --- p.69 === Chapter 4.1.3 --- Lattice constants --- p.72 === Chapter 4.1.4 --- Transport properties --- p.73 === Chapter 4.1.5 --- Magnetic properties --- p.74 === Chapter 4.2 --- Fluorine and Yttrium co-doped SmFeAsO --- p.78 === Chapter 4.2.1 --- Morphologies and microstructures --- p.79 === Chapter 4.2.2 --- Phase and composition --- p.82 === Chapter 4.2.3 --- Lattice constants --- p.84 === Chapter 4.2.4 --- Oxidation state --- p.85 === Chapter 4.2.5 --- Transport properties --- p.88 === Chapter 4.2.6 --- Magnetic properties --- p.89 === Chapter 4.3 --- Quality control of the superconducting products --- p.94 === Chapter 4.3.1 --- Intermediate product SmAs --- p.95 === Chapter 4.3.2 --- Intermediate product FeAs --- p.104 === Chapter 4.3.3 --- Effects of annealing temperature --- p.110 === Chapter 4.4 --- Summary --- p.112 === References --- p.112 === Chapter Chapter 5 --- Discussions --- p.113 === Chapter 5.1 --- Effects of F doping --- p.113 === Chapter 5.2 --- Effects of YF doping --- p.115 === Chapter 5.3 --- Improvements in the quality of the superconducting samples --- p.117 === Chapter 5.4 --- Summary --- p.124 === References --- p.125 === Chapter Chapter 6 --- Conclusions and Suggestions for Future work --- p.126 === Chapter 6.1 --- Conclusions --- p.'126 === Chapter 6.2 --- Suggestions for future work --- p.128 === References --- p.130 === Chapter Appendix A --- Sealing samples in small evacuated silica capsules for DTA measurements --- p.131 === Chapter Appendix B --- AC susceptibility measurement --- p.133 === Chapter Appendix C --- Suggested readings for beginners --- p.135 === Bibliography --- p.138