【摘要】 用脉冲激光沉积（PLD）法制备了钙钛矿锰氧化物La_0.9Ce_0.1MnO₃（LCEMO）单晶薄膜.X射线衍射分析表明,薄膜具有钙钛矿赝立方结构,且沿（100）方向择优生长;电阻-温度关系给出其存在金属-绝缘体相变和庞磁电阻（CMR）效应,相变温度(T_MI)为213K;在0.1T的磁场下,其磁电阻峰值为38.5%,对应的温度为153K;其电阻在低温区满足R=R₀+R₁T²+R₂T^4.5,在高温区符合小极化子输运.薄膜在绿激光（532nm,40mW）作用下T_MI向低温方向移动;这主要是由于激光激励下体系的自旋发生了变化.且电阻与时间的变化曲线满足关系:R（t）=R₀+Aexp（—t/r）,说明薄膜在激光作用下具有明显的与自旋相关的弛豫现象.更多还原

【Abstract】 Using Pulsed Laser Deposition method,the La_0.9Ce_0.1MnO₃ thin film was epitaxial prepared on LaAlO₃ （100） single crystal substrate.The XRD result shows the film has perovskite pseudocubic structure with preferential orientation （100）.The R-T curves show the metal-insulator transition and CMR effect,and the T_MI are 213K and 223K for 0T and 0.1T,respectively.The maximum MR is 38.5% at 0.1T.Correspondingly,the peak temperature at the maximum MR is 153K.This indicates that the films display CMR effect in the mental region.The fitting results show that the data satisfy R=R₀+R₁T²+R₂T^4.5 for T<T_MI,and for T>T_MI,it is satisfied with small polaron model . The effect of the continue wave laser （532nm,40mW） on the film was also investigated.Below TMI, the resistance increases.Above T_MI there is a decrease of the resistance.The TMI shifts to the low temperature when the laser irradiates.This is attributed to the change of the spin order in the film because of photoinducing,reduce the double exchange,and change electronic transport.The resistance meets the exponential formula R（t）=R₀+Aexp（-t/τ）,which can interpret the relaxation process from the photoinduced spin correlation state.更多还原