Highly orientated growth and characterization of La_0.7Sr_0.3MnO₃ thin films with different orientations on SrTiO₃ substrates by chemical solution deposition method

La_0.7Sr_0.3MnO₃ (LSMO) thin films were successfully prepared on (100), (110), and (111) oriented SrTiO₃ substrates by chemical solution deposition method. The structural, magnetic, and magnetotransport properties were systematically studied. X-ray diffraction θ-2θ and -scan measurements results show that all the films have perfect crystalline orientation and in-plane alignment. Both the Curie temperature and metal-insulator transition temperature are almost the same for all the three orientations, about 339 K. The magnetoresistance value (MR value, defined as (R_M - R₀)/R₀ × 100%, where R_M and R₀ are the resistivity with and without applied magnetic field) for the films reaches maximum near the Curie temperature. Both the magnetization and MR value for (100) direction LSMO are the largest, and meanwhile for (111) direction are the smallest. The saturation magnetization decreases approximately proportional to T² at low temperature (T < T_c/2) for all the oriented film. Inversely, the resistivity increases proportional to T² in the same temperature range, which can be attributed to the electron-electron scattering.