Magnetic and mechanical properties of Ni-Au nanowires
- 주제(키워드) Ni-AU nanowire , Electrodeposition , magnatic , mechanical
- 발행기관 고려대학교 대학원
- 지도교수 김영근
- 발행년도 2013
- 학위수여년월 2013. 8
- 학위구분 박사
- 학과 일반대학원 신소재공학과
- 원문페이지 112 p
- 실제URI http://www.dcollection.net/handler/korea/000000046602
- 본문언어 영어
- 제출원본 000045764545
초록/요약
Fabrication of simple nanowires is no longer state-of-the-art technology, since various synthetic methods of nanowires were studied not only in top-down approaches using conventional etching techniques and MEMS (Micro-Electro-Mechanical Systems) fabrication methods but also in bottom-up approaches through CVD (Chemical Vapor Deposition), VLS (Vapor-Liquid-Solid method), hydrothermal synthesis, electrochemical synthesis and the other modified methods. We investigated synthetic method of heterostructured nanowires with different kind of materials combined in a nanowire structure as multilayered structures. Synthesis of specific structures of Ni-Au nanowire system was performed with electrodeposition method into AAO (Anodized Aluminum Oxide) nanotemplates in one-bath using difference in reduction potentials of the precursor metal ions. The formation and microstructures of nanocrystalline multilayers have confirmed by TEM (Transmission Electron Microscope) analysis and distinctive magnetic properties. Furthermore mechanical properties of single nanowires have investigated by quantitative in situ tensile testing in dual beam FIB (Focused Ion Beam) system.
more목차
1. Introduction
1.1 Overview------------------------------------------------------------ 2
1.2 Outline of dissertation ----------------------------------------------- 5
2. Theoretical Background
2.1. Synthesis of nanowires ------------------------------------- 7
2.1.1 Template based synthesis methods ------------------------------- 7
2.1.1.1 Template synthesis ------------------------------- 7
2.1.1.2 Template Assisted Growth by Pressure Injection------- 10
2.1.1.3 Electrochemical deposition ----------------------------- 11
2.1.1.4 Vapor deposition ------------------------------ 14
2.1.2 Template-free synthesis methods ------------------------------ 16
2.1.2.1 VLS Method for nanowire synthesis -------------------- 16
2.2. Nano-Magnetism ------------------------------------------- 17
2.2.1 Magnetic anisotropy ------------------------------ 17
2.2.1.1 Magnetocrystalline anisotropy------------------------ 18
2.2.1.2 Shape anisotropy ------------------------------ 19
2.2.1.3 Anisotropy in polycrystalline materials ----------------- 22
2.2.4 Hysteresis --------------------------------------- 24
2.2.5 Cylindrical confined 2-D nanostructures ------------------- 28
2.3. Mechanical properties on nanomaterials ---------------------------- 33
2.3.1 Dislocation-based deformation mechanism ---------------------- 34
2.3.2 Twinning and martensitic transformation ------------------------ 37
2.3.3 Fracture ------------------------------------------------------- 38
3. Experimental Procedure
3.1. Synthesis of nanowires --------------------------------------------- 48
3.1.1 AAO nanotemplate --------------------------- 48
3.1.1.1 Commercially Available AAO membrane --------------- 48
3.1.1.2 AAO membrane fabricated in the lab --------------- 49
3.1.2 Electrodepostion of nanowires --------------------------- 52
3.1.2.1 Single element metallic nanowires --------------------- 52
3.1.2.2 Multilayered metallic nanowires --------------------- 52
3.2. Characterization of nanowires -------------------------------------- 55
3.2.1 Structural analysis of nanowires -------------------------------- 55
3.2.2 Magnetic behaviors of nanowires --------------------------- 55
3.2.3 Mechanical properties of nanowires ----------------------------- 56
4. Results and discussion
4.1 Structural and Magnetic properties of Ni-Au nanowires ------------- 59
4.2 Mechanical properties of Ni-Au nanowires ------------------------- 77
5. Conclusion--------------------------------------------------------- 87
References----------------------------------------------------------- 89
