本文用渗流模型研究T(La1-xBx)2/3Ca1/2MnO3系统由顺磁性向铁磁性转换过程中外磁场与转换温度的关系.在平均场理论中,电阻是外磁场和温度的函数.我们发现:当外加磁场不太强时,转化温度随着外磁场的增加而线性地增加.并计算了该系统的热容量.我们理论上的计算与最近的实验观察相当符合.
On basis of a magnetic percolation model, magnetic transition has been studied for (La1-xBx)Ca1/3 MnO3 system, consisting of paramagnetie and ferromagnetic domains. In the mean-field approach,magnetic resistance as a function of temperature and magnetic field is derived analytically. Subsequently,the thermal capacitance and magnetic resistance are calculated numerically, and compared with recent measurements. It is found there is linear dependence of the critical temperature on the magnetic field,provided the magnetic field is not too strong. The theoretical predications agree well with experiments.
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