Optical, magnetic and defect studies of Ni2+ doped SrSnO3 nanostructures

Abstract

The induced ferromagnetic behaviour and defect analysis of the undoped, Ni doped SrSnO3 nanostructures are examined. The undoped and Ni doped SrSnO3 (SSO) nanostructures crystallized in the orthorhombic perovskite structure, and show local structural disorders on vibrational spectroscopic analysis. The electron micrographs are witnessed rod type morphology for pure SrSnO3 and corals for Ni doped compounds. The oxidation states of elements and presence of oxygen vacancies are identified. The sharp optical absorption behaviour resulted in reduction of optical band gap. Positron annihilation spectroscopy (PAS) studies reveal the presence of site-specific intrinsic defects of considerable concentration and their consequential effect on doping. PAS significantly showed that Schottky-type VSn and VSr-XO complexes in undoped SSO. The addition of Ni2+ results in the reduction of VSr–O and the formation of Ni2+-VO-Ni2+ defect complexes. The EPR spectra show the signal with g value of 2.2432. The appearance of RT ferromagnetism could be attributed to the defects, F-center exchange (FCE) interactions in Ni-doped SSO nanostructures.