Magnetic properties of NiO nanoparticles

Nickel oxide nanoparticles of different sizes are prepared by a sol-gel method. Samples are characterized by X-ray diffraction and transmission electron microscopy. Dc susceptibility measurements as a function of temperature and field are done for various particle sizes. We find peaks in zero field cooled susceptibility vs. temperature curves. In sufficiently low fields the peak temperature decreases with increasing particle size whereas at higher fields the peak temperature increases with increasing particle size. We propose that these nanoparticles consist of antiferromagnetically aligned core spins and a spin glass like surface layer. (c) 2005 Elsevier B.V All rights reserved.

采用溶胶 - 凝胶法制备了不同尺寸的氧化镍纳米粒子。通过X射线衍射和透射电子显微镜对样品进行了表征。对不同粒径的样品进行了随温度和磁场变化的直流磁化率测量。我们在零场冷却磁化率与温度曲线中发现了峰值。在足够低的磁场中，峰值温度随粒径增大而降低，而在较高磁场中，峰值温度随粒径增大而升高。我们提出这些纳米粒子由反铁磁排列的核心自旋和类似自旋玻璃的表面层组成。（c）2005爱思唯尔有限公司。保留所有权利。