Mn基钙钛矿样品庞磁电阻效应的Monte Carlo模拟

Monte Carlo Simulation of Colossal Magnetoresistance in Mn Based Perovskites

基于顺磁性绝缘体和铁磁金属两相随机分布的假设,对居里温度Tc 分别为330K和2 5 0K的La2 / 3 Ba1/ 3 MnO3 和La2 / 3 Ca1/ 3 MnO3 两个典型样品的电阻随温度和磁场的变化进行了MonteCarlo模拟,模拟曲线在行为上相同于文献上普遍报道的实验曲线。研究表明,Mn基钙钛矿样品中Tc 附近观察到的庞磁电阻是由于磁场引起Tc

Based on the assumption of random distribution of paramagnetic insulating and ferromagnetic metallic phases, Monte Carlo simulation for the temperature dependence of resistance without and with an applied magnetic field was performed for two typical samples, La2/3Ba1/3MnO3 and La2/3Ca1/3MnO3 with Curie temperature Tc of 330 K and 250 K respectively. The simulated curves in behavior are the same as that generally reported on both the systems. Based on that, it is argued that the colossal magnetoresistance observed near Tc in Mn based perovskites is due to the magnetic field-induced substantial increase in the volume fraction of ferromagnetic metallic phase.