采用脉冲激光沉积法制备了稀土掺杂钙钛矿锰氧化物Pr2/3Sr1/3MnO3 (PSMO)外延薄膜, 研究了薄膜在磁场、激光和电流作用下的自旋输运特性. 在低温铁磁金属相, 激光作用使薄膜的电阻增大, 而磁场和电流则诱导电阻减小; 在高温顺磁绝缘态, 外场诱导均使电阻减小. 在铁磁金属相, 外场诱导输运特性的变化可归结于外场对体系电子自旋系统的影响: 磁场和电流加强材料中eg电子和t 2g局域电子间的自旋平行, 增强了双交换作用; 激光作用可产生光致退磁效应, 减弱双交换作用. 在顺磁绝缘态, 场致电阻降低源于外场致使小极化子的退局域化效应.
The doped manganites Pr2/3Sr1/3MnO3 (PSMO)film was prepared by the pulsed laser deposition method. The spin transport properties of the film induced by the magnetic field, laser and the current field were investigated. In ferromagnetic metallic state, the laser irradiation results in the increase of the resistance, which is attributed to the photoinduced demagnetization effect. But the magnetic field and the current induce the resistance decrease because the magnetic field and the current align the magnetic moments of the nearest Mn ions and enhance the double-exchange effect. In the paramagnetic
insulating phase, the three external fields induce the decrease in the resistance, which is due to the field-induced delocalization of the small polarons.
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