铁磁性锰氧化物掺杂的ZnO压敏电阻性能研究

利用通常的电子陶瓷制备工艺制备了铁磁性锰氧化物La_07Sr_03MnO₃掺杂的ZnO陶瓷. 晶界处存在La_07Sr_03MnO₃(LSMO)和LaMnO₃(LMO)两种杂相. 样品中绝缘相LMO的含量显著影响着样品的电学性能. 掺杂后的样品仍具有一定的铁磁性. 在样品上施加磁场后，样品电阻值增加，表现为正磁电阻性质. 正磁电阻的出现，是由于磁场的存在 关键词： ZnO 压敏电阻 锰氧化物 正磁电阻

The study of ZnO varistor doped with ferromagnetic manganese oxide

ZnO varistor doped with ferromagnetic manganese oxide (La_07Sr_03MnO₃) was prepared by conventional electric ceramic technique. There are secondary phases, La_07Sr_03MnO₃ and LaMnO₃, existing at the grain boundaries. The content of insulating phase of LaMnO₃ obviously affects the electrical properties of the samples. The samples still remained ferromagnetism after doping. Applied magnetic filed could change the electrical property. The resistance increased when magnetic field was applied, showing a positive magnetoresistance (PMR) phenomenon. The existence of PMR is due to the broadening of barrier at the grain boundaries caused by the magnetic field.