晶界对庞磁电阻颗粒薄膜的磁学和输运性能的影响

采用脉冲电子束沉积技术，在Si(100)单晶衬底上沉积庞磁电阻La_0.67Ca_0.33MnO₃颗粒薄膜，并对它的磁学性能和电学输运性能进行了表征.研究晶界对庞磁电阻薄膜的物理性能的影响，结果表明，晶界的存在使得晶粒之间的耦合变弱，在变温磁化过程中表现出团簇玻璃态行为，金属—绝缘体转变温度(T_p)远远低于铁磁—顺磁转变温度(T_c).低温下电子输运具有弱局域化行为.在低磁场下，晶界的存在掩盖了La_0.67Ca_0.33MnO₃的本征磁电阻行为. 关键词： 脉冲电子束沉积 晶界 磁学和电学输运性能 庞磁电阻

The effect of grain boundaries on magnetic and transport properties in colossal magnetoresistance particle film

La_0.67Ca_0.33MnO₃ grain films have been grown by pulsed electron beam deposition technology,and their magnetic and electronic transport properties investigated in detail.The influence of grain boundaries on the physical properties of La_0.67Ca_0.33MnO₃ grain films were studied.Grain boundaries weaken the coupling between grains,resulting in a cluster spin glass state.The metal-insulator transition temperature (T_p) was shifted far below the ferromagnetic-paramagnetic transition temperature (T_c).At low temperatures,the electron transportation indicates a weak localization behavior,and under low magnetic fields,the intrinsic magnetoresisance effect is screened by the influence of grain boundaries.