研究了钙钛矿锰氧化物La2/3Sr1/3MnO3和Pr2/3Sr1/3MnO3单晶薄膜的激光诱导电阻变化特性。低温铁磁金属相,激光诱导使薄膜的电阻增大,而在顺磁绝缘相则电阻减小,同时薄膜的绝缘体-金属相变(IMT)转变温度Tp向低温方向移动。对于Pr2/3Sr1/3MnO3薄膜,当激光功率为22mW时,光致电阻相对变化的最大值约为9.6%。光诱导效应致使薄膜的电阻发生变化,并使其IMT的转变温度点向低温方向移动,主要是由于光子能激发eg向下电子的跃迁,改变体系自旋极化方向。
The photo-induced effect on the resistance of manganite Pr2/3Sr1/3MnO3 and La2/3Sr1/3MnO3 thin films have been investigated. The results shows that the resistance of the film irradiated by the laser with wavelength of 532nm increases in ferromagnetic-metallic state and decreases in paramagnetic-insulator state. The maximum of photo-induced relative change in resistance is about 9.6% for PSMO thin film. The insulator-metal transition temperature shifts to the lower temperature due to the photo exciting of the down-spin eg electrons and destroying the spin order system of the thin film.