| 研究生: |
李鎮宇 Chen-Yu Lee |
|---|---|
| 論文名稱: |
錫鎳奈米核殼結構的法拉第磁感應探討 |
| 指導教授: | 李文献 |
| 口試委員: | |
| 學位類別: |
碩士 Master |
| 系所名稱: |
理學院 - 物理學系 Department of Physics |
| 論文出版年: | 2016 |
| 畢業學年度: | 104 |
| 語文別: | 中文 |
| 論文頁數: | 72 |
| 中文關鍵詞: | 錫鎳奈米 、法拉第磁感應 、磁性鬆弛 、弛豫現象 |
| 相關次數: | 點閱:14 下載:0 |
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本篇論文討論 Sn@Ni 核殼結構奈米顆粒的磁性、超導研究與磁性
鬆弛行為,使用熱蒸鍍冷凝法的雙鍍源方式製作本樣品,經由 X 光繞
射譜圖、EDXS與 TEM判定 Sn核直徑為2.4 nm,Ni殼的厚度為 1.9 nm。
Sn@Ni 在外加磁場 Ha = 200 Oe 的阻擋溫度 TB = 43 K, ;Ha = 1 kOe
,TB = 6 K;Ha = 5 kOe,TB = 2.4 K。對其做磁化率隨著溫度變化的實
驗,可發現 Sn@Ni 具有弱自旋玻璃行為與超導臨界磁場 Hc0 = 2.9
kOe。
Sn@Ni 奈米顆粒磁性鬆弛研究具有磁化強度翻轉的行為,此行為
可得知與本樣品為核殼結構有關。磁化強度隨時間鬆弛的曲線,應有
兩個分量的貢獻,分別是殘留的磁化強度 Mr 曲線和感應的磁化強度
Mi曲線。弛豫現象與溫度、外加磁場、降場速率有關。
最後將 Sn@Ni 與本實驗室的 Au@Ni 做個比較,可得知 Sn@Ni 感
應的磁化強度百分比 Pi0比 Au@Ni 的來的強。
We report on the magnetic properties, superconductivity and magnetic relaxation
behaviors in the nano-sized Sn@Ni core@shell particles. The Sn@Ni NPs were
fabricated employing the gas-condensation method, using a chamber equipped with two
decoupled evaporation sources for separate evaporation of Sn or Ni. We use X-ray
diffraction pattern, energy-dispersive X-ray spectroscopy and transmission electron
microscopy, resulting in a mean particle core diameter of 2.4 nm and shell thickness of
1.9 nm.
In applied magnetic field Ha = 200 Oe, the blocking temperature TB of Sn@Ni is 43
K; Ha = 1 kOe, TB = 6 K; Ha = 5 kOe, TB = 2.4 K. Doing χ(T) experiment, Sn@Ni has
weak spin glass behavior and the critical magnetic field Hc0 = 2.9 kOe.
The study of magnetic relaxation behaviors of Sn@Ni NPs had inverse magnetization
behavior. It related to core@shell structure and it depended on temperature, applied
magnetic field, and turning the Ha off. M(t) should have two components: remanent
magnetization Mr and Faraday inductive magnetization Mi.
At last, we made a comparison between Sn@Ni and Au@Ni. The ratio of Faraday
inductive magnetization Pi0 of Sn@Ni had much stronger than Au@Ni.
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