(1. 浙江师范大学 化学系 物理化学研究所， 金华 321004;
2. 长江大学 化学与环境工程学院， 荆州 434100)
摘 要: 通过配合物热分解法制备MCr2O4（M=Co， Zn）纳米晶， 并对其物相、 表面微结构和磁性进行表征。 结果表明，产物为直径40 nm左右的球形粒子， 具有立方晶系尖晶石结构。 磁滞回线表明， CoCr2O4在低温下表现出明显的亚铁磁性和较强的交换偏置场， 矫顽力和交换偏置场分别为Hc=6.05×105 A/m和He=1.93×104 A/m， 饱和磁化强度Ms和剩余磁化强度Mr分别为19.86和12.63 A·m2/kg， 这可用CoCr2O4纳米晶的表面结构缺陷导致表面原子的磁结构自旋无序来解释。
关键字: CoCr2O4； ZnCr2O4； 纳米晶； 配合物热分解； 磁性
MCr2O4 (M=Co, Zn) nanocrystalline
（1. Institute of Physical Chemistry, Department of Chemistry,
Zhejiang Normal University, Jinghua 321004, China;
2. College of Chemistry and Environmental Engineering,
Yangtze University, Jingzhou 434100, China）
Abstract: MCr2O4（M=Co, Zn）nanocrystalline were synthesized by the thermolysis of complexes. Their phase, surface microstructure and magnetic properties were characterized. The results indicate that the products have a spinel structure with cubic system, and are spheric particles with crystallite size of about 40 nm. The hysteresis loops show that CoCr2O4 has a clear ferrmagnetism and an exchange bias filed at lower temperature. It is observed that the coercivity, exchange bias filed, saturation and remanence magnetization are 6.05×105 A/m, 1.93×104 A/m, 19.86 A·m2/kg and 12.63 A·m2/kg, respectively, which are explained by the magnetic spin disorder of surface atoms resulted from surface structure defects of CoCr2O4 nanocrystalline.
Key words: CoCr2O4; ZnCr2O4; nanocrystalline; thermolysis of complexes; magnetism
