Magnetotransport properties of perovskite La-Ba-Mn-O-deposited films on Si substrates

To obtain high MR ratio near room temperature in thin films grown on Si substrate, La-Ba-Mn-O thin films were prepared with various substrate temperature (TS) from 600 deg. C to 720 deg. C by RF magnetron sputtering, and the structural and magnetotransport properties were studied. All films were annealed at 800 deg. C for 30 min in ambient. The structures, magnetic properties and compositions of La-Ba-Mn-O thin films have been studied with X-ray diffraction, X-ray photoemission spectroscopy, Rutherford back-scattering spectroscopy and vibrating sample magnetometer. The MR was measured using square-probe array method in the magnetic field of 0-1.5 T. The films were polycrystalline with (1 0 0) and (1 1 0) orientations and showed pseudocubic perovskite structure. The maximum MR ratio of thin film with TS of 680 deg. C is 0.62 under a relatively low field of 1.5 T. Moreover, it is important to notice that the MR ratio reached 0.3 near room temperature in thin films with TS of 600 deg. C and 680 deg. C