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利用金属有机物分解法在石英衬底上制备了多晶Ｌａ０．６７Ｃａ０．３３ＭｎＯｘ薄膜。研究了薄膜输运特性及其与温度的关系，发现薄膜的金属一半导体转变温度Ｔｐ（约１７２Ｋ）远低于其居里温度（约２４７Ｋ）；在平行于膜面的ＩＴ磁场下，７７Ｋ～３０２Ｋ温度范围内，没有磁电阻（ＭＲ）峰，而是在Ｔｐ温度以下，有一定的平台，平台处ＭＲ值约为２１％～２４％，在Ｔｐ温度以上，ＭＲ随温度上升而迅速降低；在７７Ｋ温度下，薄膜具有显著的低场磁电阻效应。上述磁输运特性与载流子在晶界附近的输运行为如强的自旋相关散射和晶粒间自旋极化隧道效应等有关。在７７Ｋ温度下，还观察到了退磁效应引起的磁电阻垂直各向导性。
Polycrystalline La0.67Ca0.33MnOx thin films were prepared on quartz substrates by metal-organic decomposition method. The results show that the transition temperature Tp (about 172K) is far lower than the Curie temperature (about 247K). Under the IT magnetic field parallel to the film surface, the transition temperature of 77K ~ In the temperature range of 302K, there is no magnetoresistance (MR) peak, but under the Tp temperature, there is a certain platform with an MR value of about 21% -24% at the platform. Above the Tp temperature, MR rapidly decreases with temperature rise; At 77K, the film has significant low-field magnetoresistance effect. The above magnetic transport properties are related to carrier transport near grain boundaries such as strong spin-dependent scattering and intergranular spin-polarized tunneling. At 77 K the vertical anisotropy of magnetoresistance was also observed due to demagnetization.