Abstract: Using RF magnetron sputtering method, La_0.75Na_0.25MnO₃ 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. La_0.75Na_0.25MnO₃ 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.

Key words: La_0.75Na_0.25MnO₃ epitaxial film, magnetic property, transport property