Abstract: Using Pulsed Laser Deposition method, the La _0.9 Ce _0.1 MnO ₃ thin film was epitaxial prepared on LaAlO₃ (100) single crystal substrate. The XRD result shows the film has perovskite pseudocubic structure with preferential orientation (100). The R-T curves show the metal-insulator transition and CMR effect, and the T _MI are 213K and 223K for 0T and 0.1T, respectively. The maximum MR is 38.5% at 0.1T. Correspondingly, the peak temperature at the maximum MR is 153K. This indicates that the films display CMR effect in the mental region. The fitting results show that the data satisfy R=R ₀+R ₁ T ²+R ₂ T ^4.5 for T<T _MI, and for T>T _MI, it is satisfied with small polaron model．The effect of the continue wave laser (532nm, 40mW) on the film was also investigated．Below T _MI, the resistance increases．Above T _MI there is a decrease of the resistance．The T _MI shifts to the low temperature when the laser irradiates．This is attributed to the change of the spin
order in the film because of photoinducing, reduce the double exchange, and change electronic transport. The resistance meets the exponential foula R(t)=R ₀+A exp(-t/τ), which can interpret the relaxation process from the photoinduced spin correlation state.

Key words: LCEMO film, photo-induced, transport properties, electron-doped