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射频磁控溅射法制备了La2 3Ca1 3MnO3纳米薄膜 (LCMO) .该薄膜发生FM PM相变的转变点温度为Tc≈ 30 8K(近似为电阻峰值温度Tp) ;在不同温度下的光电导性质实验表明所制备的LCMO薄膜在连续激光作用时低温段(T 0 ,并在R T曲线拐点附近取得极大值 ,(ΔR R) max=4 3 5 % ;当T>Tc 时 ,ΔR R <0 ,即光电导效应 .调制激光脉冲光响应实验发现 ,光致信号强度和温度及偏置电流之间存在非线性关系 :光致电阻率增大信号极大值为偏置电流的二次函数 ,而极大值对应的温度和偏置电流成线性关系 ,同时 ,光响应有一个截止温度 ,并且存在最佳光响应偏置电流和温度条件 .分析认为LCMO薄膜的光致电阻率变化特性和材料的eg↓自旋电子的状态以及与此相应的小极化子的形成有关
La2 3Ca1 3MnO3 nanofilm (LCMO) was prepared by RF magnetron sputtering.The temperature at the transition point of the FM PM transformation was Tc≈30 8K (approximate to the peak resistance temperature Tp). The photoconductivity at different temperatures The experimental results show that the LCMO thin film prepared at low temperature (T 0), and the maximum value is obtained near the inflection point of RT curve, (ΔR R) max = 435%; when T> Tc, R R <0, that is, photoconductivity effect. Modulation of laser pulse light response experiments found that there is a nonlinear relationship between the optical signal intensity and temperature and bias current: The maximum value of the resistivity is a quadratic function of the bias current, and the temperature corresponding to the maximum corresponds to a linear relationship with the bias current. At the same time, the photoresponse has a cut-off temperature, and there is an optimum photoresponsive bias current And temperature conditions.It is considered that the change of the photo resistivity of the LCMO thin film is related to the state of the eg ↓ spintronic material of the LCMO film and the corresponding formation of the small polaron