A phenomenological description of temperature dependence of magnetoresistance in La_( 2/3)Ca_(1/3)M

• 作 者: 李西军 李可斌 杜家驹 许小军 方军 王智河 曹效文 朱警生 张裕恒
• 出 处: Science in China,Ser.A
• 发表日期: 1998年03期
• 关键词: magnetoresistance Ca MnO thin films

The electrical resistance in zero magnetic field and magnetoresistance in different external magnetic fields have been measured in a temperature range of 77-300 K. It is found that the temperature dependence of magnetoresistance can be well described by a phenomenological formula of ρ(T)=(1σ(T)= (1α(M/M s) 2+βexp(-E 0/k BT), where the fitting parameters α,β vary as the external magnetic field H changes, E 0 is the activation energy, E 0/k B =1160 K, M s is the saturation magnetization, the temperature and magnetic field dependence of M/M s is obtained by the mean-field expression.

The electrical resistance in zero magnetic field and magnetoresistance in different external magnetic fields have been measured in a temperature range of 77-300 K. It is found that the temperature dependence of magnetoresistance can be well described by a phenomenological formula of ρ (T) = (1σ (T) = (1α (M / M s) 2 + βexp (-E 0 / k BT) where the fitting parameters α, β vary as the external magnetic field H changes, E 0 is the activation energy, E 0 / k B = 1160 K, M s is the saturation magnetization, the temperature and magnetic field dependence of M / M s is obtained by the mean-field expression.