Effect of annealing conditions on the magnetism of Ni-doped La0.4Sr0.6TiO3−δ powders

Abstract La 0.4 Sr 0.6 Ti 1− x Ni x O 3−δ powders with x =0 and 2% were synthesized by the sol–gel method and characterized by a variety of techniques. We mainly investigate the effect of annealing conditions on the structural and magnetic properties of La 0.4 Sr 0.6 Ti 1− x Ni x O 3−δ powders. X-ray diffraction and transmission electron microscopy studies indicate all samples annealed at high temperature ( T >873 K) are single phase and no secondary magnetic phase in this study. By the commercial physical properties measurements system (PPMS), the sample with x =0 exhibits diamagnetic behavior, whereas all the samples with x =2% are found to be ferromagnetic even at room temperature. With the increase of annealing temperature, the ferromagnetism of the samples increases initially, and then it decreases after reaching the maximum value. The structural defects such as oxygen vacancies mediated mechanism is reasonable explanation of the magnetic properties in the present results.