Annealing effect on the properties of La0.7Sr0.3MnO3 thin film grown on Si substrates by DC sputtering

The effect of annealing on the properties of La0.7Sr0.3MnO3 (LSMO) thin film deposited on Si substrates by DC sputtering has been investigated by X-ray diffraction (XRD), electrical and magnetic measurements. As-grown films show a lower metal-insulator transition (TMI) temperature than annealed films. As the annealing temperature increases, significantly higher TMI values are observed up to 270 K. We suggest that the increase of effective hole doping, induced by cationic vacancies due to the excess oxygen, is a possible reason for the observed trend in TMI. Annealing improves the magnetic homogeneity of the grain and grain boundaries. These improvements are favorable to enhance the intrinsic properties of the compound especially the decrease of resistivity. The decrease in resistivity induces the MR ratio to increase. This result is attractive for CMR application studies.