새로운 고분자 초전도체의 이론적 제안과 합성 : Gallium linked polyphosphazene 의 합성 및 자화율, 전도도 측정

다국어 초록 (Multilingual Abstract)

Until now, many types of theories on the superconductivity have been announced by many scientists, but this scientific field is remained not yet clearly known. For the development of new types of superconducting materials, the unitary theory, which is able to explain many types of superconducting materials, is required.
In this thesis, many types of theories are reviewed following their historical and scientific approaching backgrounds in comparison and relations with each other, and the our model on the superconductivities, we call it as "Interatomic Superconducting Band(ISB) model", is simply introduced for the application to the polymer system.
From the viewpoint of ISB model, many types of organic superconductors, the only approved polymeric superconductors, poly(sulfur nitride), (-[SN]_(n)-, T_(c)=0.26K) and recent related experimental superconducting phenomena are explained.
Moreover, for the certification of ISB model, we choose a typical system, metal-linked polyphosphazene(MLPPA) which is not yet synthesized as a form of polymer, following the theoretical results of ISB.
Therefore, by introducing new co-heating method, new gallium-linked polyphosphazene(GLPPA) has been synthesized. And the structure of GLPPA is also characterized from IR, far IR, and XPS spectrum, in comparison with structure of polyphosphazene(PPA).
The magnetic property of GLPPA has also been measured by SQUID. To our surprise, two-step diamagnetic transitions were observed at 7.2K and 5.8K, and the difference of magnetic susceptibility between zero-field-cooling(ZFC) and field-cooling(FC) were observed below 4.3K under 50 Gauss. Moreover, Magnetic hysterisis is also observed at 2.00K, and 6.20K. Following their results, each step shows a characteristic transition of superconductivity. But the Resistivity data of GLPPA show a extraordinary non-zero properties and have a inner-potential by some probe potential problem, but indirect evidence of electric change is observed below 7.2K.

목차 (Table of Contents)

• Abstract = 1
• Contents = 3
• Lists of Figures = 5
• List of Tables/참조 = 7
• 새로운 고분자초전도체의 이론적 제안과 합성 = 8
• Introduction = 8
• The Historical and Theoretical Background of Superconductivity = 12
• A. 발견의 시대 = 12
• a) Two-fluid model = 15
• b) The first and second London equation = 17
• B. 이론 형성의 시대 = 19
• a) Ginzburg-Landau theory = 19
• b) BCS theory = 24
• C. 실험적 개발과 이론적 혼돈의 시대 = 30
• a) BCS theory에 대한 이론적 의구심 = 31
• b) The polaron-bipolaron model = 33
• c) Fermi-liquid theory = 36
• d) The attractive Hubbard model = 38
• e) The three-band and t-J model = 39
• D. 초전도 현상에 대한 물리적 접근의 근원적 문제점의 고찰 = 43
• a) 2e 인가 ne 인가? (Boson, Fermion 문제와 Boltzon) = 43
• Flux quantization과 Joesephson effect = 43
• b) 초전도 전자의 에너지 전달은 어디로 일어나는가? = 51
• MgB_(2)와 Lattice vibration potential = 51
• c) Interatomic Superconducting Band(ISB) model = 56
• 통계적 이론의 의미와 간단한 시스템으로의 적용 = 56
• 유기물 및 고분자 초전도체 합성을 위한 제안 = 62
• Two step Diamagnetic Transitions of Gallium-Linked polyphosphazene = 65
• A. The direction of synthesis on the base of ISB model = 65
• B. Synthesis = 69
• C. Characterization = 71
• a) UV & IR spectrum = 71
• b) XPS analysis = 76
• D. Magnetic susceptibility = 82
• E. Resistivity = 87
• Conclusion = 95
• References = 100