Jae-Hyun Ha. (2024). Defect-engineering of electric and magnetic thin films with broken crystal symmetry. doi: 10.22677/THESIS.200000798204
Type
Thesis
Description
Correlation, Crystal structure, Defect, Symmetry
Table Of Contents
Ⅰ. Introduction 1 Ⅱ. Research background 3 2.1 What is a solid 3 2.2. Why is periodicity important 7 2.3 Defects 9 2.3.1 Volume defects 9 2.3.2 Interfacial defects 9 2.3.3 Line defects 9 2.4. Common techniques to assess materials 9 2.4.1 XRD 13 2.4.1.1 Brief history of x-ray 13 2.4.1.2 X-rays and elastic scattering with condensed matter 13 2.4.1.3 Components of x-ray diffractometer 13 2.4.1.4 Crystallographic information of XRD patterns 13 2.4.2 Electron microscope 17 2.4.2.1 Brief principle of a scanning electron microscope 17 2.4.2.1.1 Basic configuration of SEM 17 2.4.2.1.2 Electron gun 17 2.4.2.1.3 Condensed lens 17 2.4.2.1.4 Specimen room 17 2.4.2.1.5 Principal measure factors in SEM 18 2.4.2.2 Brief principle of a transmission electron microscope 21 2.4.2.2.1 Preparation of TEM specimens and configuration of TEM 21 2.5 Electrical properties in a matter 24 2.5.1 Drude model of metal 24 2.5.2 AC electrical resistivity 26 2.5.3 Metal to insulator transition 26 2.6 Magnetic properties in a matter 30 2.6.1 Magnetic ordering 30 2.6.2 Ferromagnetism 30 2.6.3 Antiferromagnetism 34 2.6.4 Exchange anisotropy 36 2.6.5 Spin glass 38 2.7 Defect-engineering 39 Ⅲ. Tunable metal-insulator transition of V2O3 thin films strained by controlled inclusion of crystallographic defect 40 3.1 overview 40 3.2 Experimental section 41 3.2.1 Deposition of V2O3 films 41 3.2.2 Structural characterizations 41 3.2.3 Measurements of electrical properties 42 3.2.4 Measurements of optical properties 42 3.3 The effect of spatial alignment of multiple grains in V2O3 films on MIT temperature and the transition rate 42 3.4 The effect of controlled amount of stacking faults in the films 51 3.5 Conclusion 63 Ⅳ. Tuning magnetic properties through mixed-valency in amorphous vanadium oxide thin films 64 4.1 Overview 64 4.2 Deposition of various vanadium oxide films 65 4.3 Structural characterization 65 4.4 Magnetic properties 68 4.5 Analysis of V ion oxidation state 73 4.6 Conclusion 77 Ⅴ. Magnetic glassy characteristics of PtCoNiO thin film with broken crystal symmetry 78 5.1 Overview 78 5.2 Preparation of films and TEM specimens 79 5.3 Structural characterization 79 5.4 Ferromagnetic and antiferromagnetic exchange couplings 94 5.5 Magnetic glassy characteristics 97 5.6 Conclusion 106 VI. Summary 107 References 109
