| 研究生: |
黃竑杰 Hong-Jie Huang |
|---|---|
| 論文名稱: |
零維銦奈米微粒的超導參數探討 The superconducting parameters of zero-dimensional Indium nanoparticles |
| 指導教授: |
李文献
Wen-Hsien Li |
| 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 |
| 畢業學年度: | 92 |
| 語文別: | 中文 |
| 論文頁數: | 72 |
| 中文關鍵詞: | 耦合強度 、穿透深度 、銦奈米微粒 、臨界溫度 、臨界磁場 |
| 外文關鍵詞: | critical magnetic field, penetration depth, coupling strength, In nanoparticle, critical temperature |
| 相關次數: | 點閱:15 下載:0 |
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論文摘要
製作銦奈米微粒是採用真空蒸鍍法,改變氬氣壓力與鍍源溫度製作出不同粒徑大小的銦奈米微粒。腔體內氬氣壓力越大所成長的奈米微粒粒徑越小;鍍源溫度越高所成長的奈米微粒粒徑越大。
磁化率實驗,大致上分為兩部份:一部份為穿透深度的分析;另一部份為耦合強度的擬合。穿透深度的分析是利用London理論得到一磁化率擬合公式,當銦奈米微粒變小,穿透深度也隨之變小,當粒徑約在10nm附近時,穿透深度突然隨粒徑變小而變得非常的大,這表示當粒徑小於10nm以下時,其抗磁效應就會漸漸消失。
另一部份耦合強度擬合,可發現臨界磁場隨粒徑變小而變大,相同地,在粒徑14nm附近,其臨界磁場最大,在14nm以下臨界磁場就會隨粒徑變小而變小。對每個樣品作擬合耦合強度值,得知65nm的值為1.28、17nm的值為1.46、14nm的值為1.64、12nm的值為1.37與8nm的值為1.54。
Abstract
Indium nanoparticle is produced by evaporation, changing Argon pressure and the temperature of W-boat to make different Indium nanoparticle diameters. The larger particle diameter is grew in higher Argon pressure, and the smaller one is grew in lower temperature.
The experiment of susceptibility is mainly divided into two parts, one is London penetration depth and the other is the superconducting coupling strength. London penetration depth is according to London theorem to get London equation. Indium nanoparticle becomes small along with the small penetration depth and when particle diameter is around 10-nm, the penetration depth will suddenly becomes unusual large with the small diameter of particle. This scenario indicates when the particle diameter is less than 10-nm, then diamagnetic screening effect will diminish gradually.
In the superconducting coupling strength part, it shows that the critical magnetic field becomes large with particle diameter becomes small. Similarly, when particle diameter approximates 14-nm, the critical magnetic field approaches the maximum value. Nevertheless, when the particle diameter is lower 14-nm, the smaller particle diameter causes the smaller critical magnetic field. For each sample in the coupling strength value, knowing that the particle diameters are equal to 65-nm, 17-nm, 14-nm, 12-nm and 8-nm then the coupling strength values are 1.28, 1.46, 1.64, 1.37 and 1.54 respectively.
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