Colossal Magnetoresistance of La-Ca-Mn-O Films

We have investigated the magnetoresistance and magnetization of the thin films of LaCa0.25Mn1.2O3+δ. The films were prepared by rf-sputtering at 650°C on single crystal LaAlO3(100). MgO(100) and rough MgO surfaces, with a thickness of 480 nm, and they were thermally treated at 1050°C. The dependence of the magnetoresistance on the grown conditions such as substrate materials and the surface roughness of the substrate was examined. The significant magnetoresistance appeared at different temperatures when the film epitaxy changed