銅氧核殼奈米顆粒的雙分量自旋極化; Tow-components spin polarization in Cu/O core-shell nanoparticles

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题名:	銅氧核殼奈米顆粒的雙分量自旋極化;Tow-components spin polarization in Cu/O core-shell nanoparticles
作者:	李宗儒;Zong-Ru Li
贡献者:	物理研究所
关键词:	銅;自旋極化;Cu;spin polarization
日期:	2008-06-20
上传时间:	2009-09-22 10:59:48 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	本實驗採用熱蒸鍍法製備兩組銅奈米顆粒後至於空氣中分別得到在外圍包覆不同氧化厚度的銅氧核殼奈米粒子，經由X光繞射圖分析我們得到其中四組銅與氧化亞銅的比例為1:1、3:1、3:2、4:21，最後經由X光繞射寬的擬合以及AFM粒徑影像的比對我們定義出樣品的粒徑為7.2、8.8、9、12.4 nm。經由磁化強度與磁化率的測量得知系統中具有兩個磁分量因此使用兩個朗之萬函數加一線性抗磁項來描述此其磁性，我們推測兩個磁分量分別為銅以及氧化亞銅自旋極化，銅的自旋極化飽和磁化強度隨溫度無明顯變化趨勢，而由氧化亞銅自旋極化的飽和磁化強會隨溫度升高而遞減，兩者的磁矩數皆隨溫度升高而增加，此外比較各組樣品由銅所產生的磁性以及抗磁性質，發現其強度會隨銅粒徑的減少而增強。 Five core shell Cu/Cu2O nanoparticles were fabricated by thermal evaporation method. The outer Cu2O shell was formed by expose the Cu nanoparticle to the air . X-ray difference studies show that the mole ratio of Cu/Cu2O in the four samples are 1:1, 3:1, 3:2, 4:21. The mean particle diameters were determinded from the X-ray peak profiles and the AFM images . The mean diameters are 7.2, 8.8, 9, 12.4 nm. Magnetization and ac magnetic susceptibility measurements were performed to study the magnetic properties. Dual Langevin function plus a linear diamgnetism term were may be used to describe the M-H curves, which represent the contribution from Cu spin polarized, Cu2O spin polarized, and diamgnetism respectively. No obvious change in the saturate magnetization of Cu moment was found, whereas that of Cu2O decreases with increased temperature. The average particle moments of both Cu and Cu2O component were found to increase when temperature is increased. On other hand, the diamgnetism and saturation magnetization of Cu increase as particle diameter is decreased.
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