稀磁半导体Hg0.89Mn0.11Te磁化强度及磁化率的研究

利用MPMS-7(magnetic property measurement system)型超导量子磁强计对垂直布里奇曼法生长的Hg_0.89Mn_0.11Te晶片磁化强度变化规律进行了测量.试验采用了两种不同的外场和冷却条件.首先在5 K恒温下，-5200到5200 kA/m范围内改变磁场强度进行了测定.然后维持800 kA/m恒定磁场，分别在有场冷却和无场冷却条件下，从5到300 K范围内改变温度，研究了变温条件下的磁化特性.并采用分子场近似模型，用类布里渊函数，最小二乘法对磁化强度随磁场强度变化的实验结果进行拟合和分析，结果表明，Mn²⁺离子之间存在反铁磁相互作用.磁化率和温度关系分析表明：在测试范围内Hg_0.89Mn_0.11Te是单一的顺磁相，在高温区磁化率和温度服从居里-万斯定律，呈线性关系，低于40 K时，磁化率和温度的关系偏离居里-万斯定律，表现出顺磁增强现象. 关键词： 0.89Mn_0.11Te')" href="#">Hg_0.89Mn_0.11Te 磁化强度 磁化率 类布里渊函数

Magnetization and susceptibility of diluted magnetic semiconductor Hg0.89Mn0.11Te

The magnetization measurements of Hg_0.89Mn_0.11Te sample grown by vertical Bridgman method have been carried out at 5 K under external field from -5200 to 5200 kA/m, and at 800 kA/m from 5 to 300 K with zero-field-cooling and field-cooling respectively using the superconducting quantum interference device (SQUID) magnetometer. Based on the mean field theory, a modified Brillouin function is well fitted with the data of magnetization vs magnetic field over the entire magnetic field range. The analysis indicates that there is an antiferromagnetic exchange coupling between Mn ions. The results of reciprocal susceptibility vs temperature show Curie-Weiss behaviors at temperatures above 40 K and a deviation from the Curie-Weiss law at temperatures from 5 to 40 K, which shows that the antiferromagnetic exchange coupling between Mn ions increases with decreasing temperature. The result was explained by extending higher-order terms in the calculation of susceptibility. Hg_0.89Mn_0.11Te is a paramagnetic material in temperature range from 5 to 300 K.