通过射频磁控溅射在单晶LaAlO3(100)衬底上生长了膜厚为120nm的La0.75Na0.25MnO3外延膜. 通过X射线衍射、超导量子干涉仪、直流四探针法对其进行了表征. 结果表明, 薄膜为(100)取向外延膜. 居里温度TC=270K, 在居里温度附近, 发生铁磁-顺磁转变. 此材料呈现出典型的自旋玻璃特性, 是由于应力造成的. 在室温附近, 此材料在1T磁场下, 其磁电阻极大值为40.3％. 80K<T<210K时, 其输运机制为电子-电子散射, 电阻率满足ρ=ρ0+ρ1T2+ρ2T5; 220K<T
Using RF magnetron sputtering method, La0.75Na0.25MnO3 film with thickness of 120nm was epitaxially grown on (100) LaAlO3 single-crystal substrate. The thin film was characterized by X-ray diffraction, Superconducting quantum interference device and DC four probed method. The results indicate that the thin film shows a well epitaxial direction of (100) and the Curie temperature is 270K. Near the Curie temperature, the magnetic property shows a transition from ferromagnetic to paramagnetic character. La0.75Na0.25MnO3 thin film exhibits a characteristic spin glass state, which is due to strain effect. The thin film exhibits a quite distinctive magnetoresistance effect which is 40.3％ near the Curie temperature when the magnetic field is 1T. Transport properties indicate that the resistivity satisfies the formula of ρ=ρ0+ρ1T2+ρ2T5 from 80K to 210K which is due to electron-electron scattering, the resistivity satisfies phase separate percolation model from 220K to TMI, the resistivity satisfies polarons model when the temperature is above TMI which is due to the existence of the small polarons nearest hopping.
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