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在 10— 80 0K的温度范围内用X射线衍射方法测量了DyMn2 Ge2 化合物的晶格常数与温度的变化关系 ,观察到高温时DyMn2 Ge2 由顺磁状态到反铁磁状态的自发磁相变伴随着晶格常数a的负的磁弹性异常现象 .在4 2K— 2 0 0K的温度范围内测量了DyMn2 Ge2 的交流磁化率 .在交换相互作用的分子场模型近似下 ,从理论上分析讨论了DyMn2 Ge2 的低温自发磁相变和场诱导的磁相变 .计算了DyMn2 Ge2 单晶的磁化强度与温度的变化关系以及不同温度下外磁场沿晶轴c方向时的磁化曲线 .理论分析和计算结果表明 ,温度低于 33K时在DyMn2 Ge2 中观察到的场诱导的一级磁相变为由亚铁磁状态 (Fi)到中间态 (IS)相变 .
The relationship between the lattice constants and the temperature of DyMn2Ge2 compounds was measured by X-ray diffraction in the temperature range of 10-80 ℃. The spontaneous phase transformation of DyMn2Ge2 from paramagnetism to antiferromagnetic state was observed at high temperature The negative magneto-elastic anomaly of the lattice constant a was measured.The AC susceptibility of DyMn2Ge2 was measured in the temperature range of 4 2K-200K.When the molecular field model of exchange interaction was approximated, DyMn2Ge2 at low temperature and field-induced magnetic phase transition.The relationship between magnetization and temperature of DyMn2Ge2 single crystal and the magnetization curve of the external magnetic field along the c axis of the crystal at different temperatures were calculated.Theoretical analysis and calculation The results show that the field-induced first order magnetic phase observed in DyMn2Ge2 at temperatures below 33K changes from ferrimagnetic state (Fi) to intermediate state (IS).