Size Dependence of Crystal Structure and Magnetic Properties of NiO Nanoparticles in Mesoporous Silica

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• 作者：Takayuki Tajiri ; Seiya Saisho ; Masaki Mito ; Hiroyuki Deguchi ; Kensuke Konishi ; Atsushi Kohno
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 15, 2015
• 年：2015
• 卷：119
• 期：2
• 页码：1194-1200
• 全文大小：367K
• ISSN：1932-7455

文摘

We synthesized NiO nanoparticles in the pores of mesoporous silica, with particle sizes ranging from 2.6 to 22 nm, and investigated their crystal structure and magnetic properties. The size dependence of the crystal structure exhibited a change in behavior across the critical size of 3 nm. The lattice constants attained maximal values at approximately 3 nm and asymptotically decreased with increasing particle size, reaching the values for the bulk crystal. The rhombohedral distortion of crystallographic structure increased with decreasing particle size for particle sizes below 鈮?0 nm and was maximum at 鈮? nm. The size dependence of lattice strain also exhibited a maximum at 3 nm. The magnetic properties such as the coercive field, anisotropy energy, blocking temperature, and shell moment exhibited maxima for particle sizes between 3 and 10 nm. These results suggest that the magnetic behavior is generated by the change in the magnetic anisotropy constant originating from the changes in the crystal structure.