利用金属有机物分解法在非晶石英衬底上成功地制备了具有 (202) 择优取向的多晶 La1－ x－ SrxMnOz 薄膜。原子力显微镜观察显示薄膜具有疏松的结构缺陷。在室温下，观察到薄膜磁电阻随 外加磁场变化具有优良的线性特征， 10 kOe磁场下，磁电阻值达到 5％。在 77 K 低温下，薄膜具有 显著的低场磁电阻效应， 2 kOe 磁场下的磁电阻值达到 11％。薄膜的电阻－温度关系具有平缓的 金属－绝缘体转变，转变温度远低于其居里温度；在 8 kOe磁场下，薄膜的磁电阻随温度下降而单调 上升。上述薄膜的磁输运特性与其结构缺陷 (包括晶界及疏松 )有关。
Polycrystalline La1－ xSrxMnOz thin films with (202) preferred orientation were successfully synthesized on amorphous quartz substrates by metal－ organic decomposition (MOD). Porous structure in the films was revealed by atomic force microscope. Good linearity of magnetotransport property and about 5％ magnetoresistance (MR) ratio under 10 kOe field are obtained at room temperature. A large MR ratio of about 11％ under 2 kOe field is observed at 77 K, showing an obvious low－ field MR effect. The temperature dependence of resistance presents a smooth metal－ insulator transition far below the magnetic transition, and the MR monotonically increases with decreasing temperature under 8 kOe field, both of which are related to the structural defects in the films including grain boundaries and porosity.
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