La2/3Sr1/3MnO3/ZnO混合物薄膜的磁电阻和伏安特性研究

利用脉冲激光沉积的方法在Si（100）氧化成SiO₂的基片上制备了(La_2/3Sr_1/3MnO₃)_x/(ZnO)_1-x混合物薄膜，研究了薄膜的磁电阻和伏安特性. X射线衍射分析表明，除了衬底SiO₂的衍射峰以外，分别出现了La_2/3Sr_1/3MnO₃（101）的衍射峰和ZnO（002）的衍射峰，且它们形成了两相共存体系. 实验表明：x=0.3的混合物薄膜表现为半导体导电特性，而x=0.4的样品则出现了典型的金属绝缘相变. 所制备的样品表现出了低场磁电阻效应和非线性伏安特性. 在0.7T磁场的作用下，x=0.3的样品在温度为60K时取得的最大磁电阻值为28.8%. 通过对伏安关系拟合表明，在La_2/3Sr_1/3MnO₃和ZnO颗粒之间存在一定的耗尽层，且产生了界面缺陷态.

Magnetroresistance and Current-voltage Characteristics in La2/3Sr1/3MnO3/ZnO Composite Films

agnetroresistance and current voltage characteristics of the composite (La_2/3Sr_1/3MnO₃)_x/(ZnO)_1-x films prepared by the pulsed laser deposition method on Si(100) substrates oxidized by SiO₂ were investigated. XRD patterns indicate that ZnO and LSMO have (002) and (101) dominant orientations, respectively, and they form the coexisting system of two phases. Experimental results show the film with x=0.3 favors a semiconductive conduction and the film with x=0.4 exhibits the typical insulator metal (I-M) transition. The films have the low field magnetoresistance（LFMR） effect and the nonlinear current voltage characteristics. The maximum LFMR value of the film with x=0.3 is about 28.8% at T=60K under an applied magnetic field of about 0.7T. The current voltage fitting shows that a great number of interface states appear at the depletion between La_2/3Sr_1/3MnO₃ and ZnO grains due to the mismatch of the lattice.