Pulsed Laser Deposition Method Cmr Thin Films And Its Characteristics

A three-dimensional numerical model for laser-ablated target using the finite differential technique is given during the process of laser -deposited films in this paper. The model takes into account the finite dimensions of the target; the laser beam is treated as Gauss distribution, and the surface heat losses due to convection and radiation. According to the model a three-dimensional temperature distribution on the surface and inside the target can be obtained. The thickness of ablation and parameter of laser is forecasted. Using the numerical model performs the temperature field of pulse laser ablation and the range of power density of laser is 2 ⁵ J/cm2 on La₂/3Sr₁/3MnO₃ target. The numerical simulation results are considered to be consistent with practical cases.Perovskite crystal and epitaxial growth of thin film of La₁/3(Ca₂/3Sr₁/3) ₂/3MnO₃ was prepared on LaAlO3 (012) single crystal substrate by pulsed laser deposition. The structural and morphology of the film were studied by X-ray diffractometry, infrared transmission and atomic force microscopy. The results show that the film is of preferential orientation. A transport property of thin film was determined using a four-probe method, and the temperature dependence of resistance shows semiconducting behavior, and no metal-semiconductor transition temperature Tp of the films in the temperature range of 77K-400 K. Electron-doped manganese oxide target La₀.9Zr₀.1iMnO₃ has been fabricated. The experimental results shows a metal-insulator transition temperature Tp of 118K and a magnetoresistance radio of-47.5% at 0.7T.