鉍奈米顆粒間交互作用對磁矩的影響

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/80702

Title:	鉍奈米顆粒間交互作用對磁矩的影響
Authors:	林哲誠;Lin, Zhe-Cheng
Contributors:	物理學系
Keywords:	自旋極化;奈米顆粒
Date:	2019-07-10
Issue Date:	2019-09-03 15:00:04 (UTC+8)
Publisher:	國立中央大學
Abstract:	使用低真空熱蒸鍍冷凝法製備奈米鉍顆粒，使用 X-ray diffraction 探測樣品的繞射譜圖，利用GSAS進行分析X光繞射譜圖，得知樣品晶格屬於菱方體，含有氧化鉍(Bi2O4)，透過施瑞爾分析粒徑大小為13 nm。將此樣品委託國立東華大學奈米科技研究中心，使用超導量子干涉儀(SQUID)量測奈米顆粒的磁性，實驗項目有：隨外加磁場的變化，所對應磁化強度的變化、隨著環境溫度(1.8 K~300 K)的變化，所對應磁化強度的變化。經由測量出的數據，可以觀察到自旋極化的現象，並利用修正過的朗之萬函數以及反磁項來進行描述。在擬合過程，發現磁矩無法完全感受外加磁場，因此在公式增加一個參數，來表示實際磁矩感受到的磁場。經過壓合改變粒子間距後，可以發現因為交互作用影響下，導致飽和磁矩隨著顆粒間距縮短而增加、奈米顆粒的自發磁性隨著間距縮短而減少。 ;The nano-sized bismuth powder samples were fabricated by the thermal evaporation method. We used XRD to get XRD patterns. And then analyze with the result show that the sample is belong Rhombohedral and contain some bismuth oxide. The particle size is 13 nm by Sherrer formula. Take this nano-particle samples to Nanotechnology Research Center in the National Dong Hwa University to determine the magnetic. The experiments are determining the magnetization at different applied magnetic fields and temperatures. Use these datas to realize there is spin polarization in the nano-particles. The sample can be described by a modified Langevin function plus a modified diamagnetic term. We change particles range by cold press the particle assembly to find out what will different saturation magnetization Ms and particle moment μp. The particle moment of the sample decreases as f is increased. The saturation magnetization of the sample increased as f is increased.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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