近年來，由於自旋電子元件的蓬勃發展，像是硬碟磁頭、磁阻式隨機存取記憶體等，磁性材料的研究越趨重要。在奈米尺度下，很多的物理性質會受到改變，為了了解磁性奈米線不同於塊材的熱傳導，本文將研究磁性奈米線隨磁場和溫度變化的熱傳導係數。
磁性結構主要使用電子束微影以及電子槍鍍膜系統來製作，接著使用四點量測方法測量結構磁阻變化，最後利用樣品本身加電流發熱及電阻檢溫的方法得到結構的熱傳導係數。
在磁場的影響下，鎳線的熱傳導係數明顯的下降，而電阻率卻沒有改變，因此，發現在磁場中，磁振子受到磁場抑制的影響，磁性材料的勞倫茲數隨著磁場明顯的下降，打破了威德曼-法蘭茲定律。

In recent years, due to the rapid development of spintronic devices such as hard drive heads, magnetic random access memory, etc., research of magnetic materials become more important. In nanoscaled some of materials properties is different. In this thesis, we study the relationship between thermal conductivity and magnetic field and that between temperature of nickel nanowires.
Nano-scaled magnetic structures are fabricated by using e-beam lithography and e-beam evaporation system. The thermal conductivity of the structures is measured by electrical resistance thermometry on self-heated structure.
The thermal conductivity of the structures decrease with magnetic field but the electron conductivity are all the same. The calculated Lorenz numbers (from the thermal and electrical conductivity data) of nickel nanowire decrease with magnetic field. We found a way to change Lorenz number and broken the Wiedemann-Franz law.

摘要 II
Abstract III
致謝 IV
目錄 V
圖、表目錄 VII
第一章、 緒論 1
1.1 前言 1
1.2 研究動機 2
1.3 研究方法 3
第二章、 理論基礎與文獻回顧 4
2.1 熱傳導係數 4
2.1.1 電子的熱傳導 5
2.1.2 晶格振盪-聲子 8
2.1.3 聲子的熱傳導 10
2.1.4 自旋波 16
2.2 熱傳導係數之測量 19
2.2.1 熱傳導係數之直接量測 19
2.2.2 熱傳導係數之間接量測 21
2.2.3 自發熱、電阻檢溫熱傳導係數量測 24
2.2.4 奈米線的熱傳導性質 26
第三章、 研究方法 34
3.1 磁性結構製作 34
3.2 磁阻測量 38
3.3 電阻溫度係數量測 39
3.4 熱傳導係數量測 40
3.4.1 熱傳導係數隨磁場變化的量測 40
3.4.2 熱傳導係數隨溫度變化的量測 42
第四章、 結果與討論 45
4.1 懸空奈米線樣品結構 45
4.2 奈米線磁阻量測 46
4.3 奈米線電阻溫度係數 50
4.4 懸空奈米線熱傳導係數 51
4.4.1. 熱傳導係數隨磁場的變化 52
4.4.2. 熱傳導係數隨溫度的變化 58
第五章 結論 64
參考文獻 66

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