中文摘要：

通过射频磁控溅射,在单晶LaAl O3（100）衬底上生长了膜厚为120 nm的La0.75Na0.25MnO3外延膜.应用X射线衍射仪、直流四探针法对其结构及电流诱导效应进行了系统研究.X射线结果表明：薄膜具有赝立方钙钛矿结构,为（100）取向外延膜.电阻率与温度关系表明La0.75Na0.25MnO3薄膜在275 K附近发生金属与绝缘体转变.电流在0.5～4 mA范围内,薄膜的峰值电阻率随电流增大而减小,在4 mA下获得了15.9%的峰值电阻率变化,并应用相分离理论给出了合理的解释.

英文摘要：

Using the magnetron sputtering method,La0.75Na0.25MnO3 film with the thickness of 120 nm was epitaxially grown on LaAlO3（100） single-crystal substrate.The film was characterized by the X ray diffraction and the Dc four probe method.The X-ray diffraction patterns show that the thin film is a pseudo-cubic perovskite type structure with the epitaxial direction of（100）.The resistivity-temperature curve shows that the film undergoes metal-insulator transition at 275 K.The peak resistivity decreases with the increment of the currents between 0.5～4mA and that of the 15.9% is obtained at 4mA.The results are reasonably explained by phase-separation theory.