粒状氧化铁的磁粘滞性  

On the Magnetic Viscosity of Granular γ Fe 2O 3 Particles

作　　者：侯登录[1,2,3] 严振庄[1,2,3] 鹿平 邵素霞[1,2,3] 聂向富 罗河烈[1,2,3] 

机构地区：[1]河北师范大学物理系 [2]河北师范大学实验中心 [3]中国科学院物理研究所

出　　处：《河北师范大学学报（自然科学版）》1997年第3期261-265,共5页Journal of Hebei Normal University：Natural Science

基　　金：北京中关村地区联合分析测试中心资助

摘　　要：制备了粒状γＦｅ２Ｏ３微粉。透射电子显微镜观察了颗粒的形貌；Ｘ射线衍射确定了样品的相组成和颗粒的平均粒度；振动样品磁强计测量了样品在不同温度下的磁化曲线和磁滞回线。利用趋近饱和定律求出粒状γＦｅ２Ｏ３微粉在不同温度下的有效磁各向异性常数ＫＥ。样品的有效磁各向异性常数大于γＦｅ２Ｏ３的磁晶各向异性常数，通过测量磁粘滞系数和不可逆磁化率，得到了不同温度下的涨落场Ｈｆ和激活体积Ｖｆ，推导了Ｈｆ和Ｖｆ的理论表达式，理论与实验结果基本一致。The granular γ Fe 2O 3 powders are prepared.The shapes of the particles are observed by TEM.The phase and particles mean sizes are determined by XRD.Using Vibrating Sample Magnetometer(VSM),the magnetic properties are measured at different temperatures.By the law of approach to saturation(LATS),the effective magnetic anisotropy constants at different temperatures are calculated.The effective magnetic anisotropy constants of the granular γ Fe 2O 3 powders are larger than the magnetocrystalline anisotropy constant of γ Fe 2O 3.By measuring the magnetic viscosity cofficient S and irrenersible susceptibility χ irr ,the fluctuation field H f and the effective activation volume V f at different temperatures are obtained.The theoretical expressions of H f and V f are derived.The calculated results are consistent with the experimental results.It is shown that the magnetization reversal process of granular γ Fe 2O 3 is coherent rotation.

关 键 词：磁记录材料 磁粘滞性 反磁化机理 氧化铁 

分 类 号：O482.54[一般工业技术—材料科学与工程] TQ586.1[理学—固体物理]