氧化銅奈米顆粒反鐵磁與鐵磁耦合研究;Antiferromagnetic and ferromagnetic coupling of CuO nano particles

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/65267

Title:	氧化銅奈米顆粒反鐵磁與鐵磁耦合研究;Antiferromagnetic and ferromagnetic coupling of CuO nano particles
Authors:	江建鋒;Jiang,Jian-fong
Contributors:	物理學系
Keywords:	氧化銅;粒徑擬合;奈米顆粒;自旋極化;磁性;CuO;size fitting;nano particle;spin polarization;magnetic property
Date:	2014-07-11
Issue Date:	2014-10-15 14:48:00 (UTC+8)
Publisher:	國立中央大學
Abstract:	我們使用平均粒徑為1 μm的氧化銅顆粒命名為CuO_Mirco，並使用熱蒸鍍法來製備銅奈米顆粒且於空氣中加熱氧化後得到氧化銅奈米顆粒，將重複5次得到的樣品加以混合並命名為CuO_Nps。為了探討氧化銅顆粒從微米尺度奈米化的磁特性，對上述兩個樣品分別進行一系列的M-H及M-T量測。微米尺度的CuO顆粒存在一弱飽和磁化強度，並隨著粒徑奈米化而增強約兩個數量級。且反鐵磁化率χ_AFM也隨粒徑奈米化有變大現象。有別於CuO_Mirco樣品，CuO_Nps樣品透過surface spin和spin wave excitation可以描述飽合磁化強度M_s隨溫度的變化，透過溫度呈反比的函數來描述反鐵磁化率χ_AFM在大於5 K的變化。 ;The 5 sets of Cu nanoparticles assemblies were fabricated by employing the thermal evaporation method, and then all oxidized into CuO phase by using a heating plate at atmosphere condition. The X-ray diffraction patterns of these 5 sets of CuO nanoparticles assemblies show no significant difference, and were mixed into one CuO nanoparticles sample. The magnetic properties of nano-size and micro-size CuO particles were studied in order to search for the ferromagnetic transition. The ferromagnetic saturation magnetization Ms of nano-size CuO particles is found to be greater than that of micro-size one by a factor of 102. The thermal profile of Ms of nano-size CuO can be described by Bloch’s law plus a surface spin disorder term. The antiferromagnetic susceptibility also increases in nano-size particles, which is inversely proportional to the temperature at 5-300 K.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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