Annealing effect on the physical properties of La_0.7Sr _0.3MnO₃ thin films grown on si substrates prepared by chemical solution deposition method

The LSMO films were prepared on Si substrates by chemical solution deposition method. The films were annealing in air and O₂ atmosphere. All films have perfectly crystallized. Compared with the LSMO films annealing in air, the residual and saturation magnetic moment value were much lower for the films annealing in O₂. The T_c of the LSMO films annealing in O₂ is higher about 15 K than that annealing in air. The variation of magnetization and Tc with annealing in O₂ is thus consistent with the change of Sr content and is almost certainly related to the Mn³⁺/Mn⁴⁺ ratio. The MR value is decreased with the increasing temperature. It is observed that the transport properties, both the resistivity and the magnetoresistance value, have similar variation behavior. It is because that the La(Sr) vacancies (δ > 0) are expected to have indirect perturb the conduction path. The resistivity and the MR value at 7 T of the both films are (0.145 Ω.cm, 59.3%), (0.208 Ω.cm, 60.0%), respectively.