Role of holes states on metal to insulator transition and collapse of magnetic ordering in LaFe1−xNixO3 (x = 0.0–0.5)

Polycrystalline LaFe1−xNixO3 (x = 0.0, 0.1, 0.3 and 0.5) have been prepared by the standard solid state reactions method. The phase formation has been confirmed by the powerful synchrotron X-ray diffraction experiment. In order to investigate the effects of Ni doping on the oxidation state, spin state and the magnetic ordering of the iron cations, 57Fe Mössbauer Spectroscopy has been carried out at room temperature. Iron is present as Fe3+ in high spin state in LaFeO3. Ni doping has no effect on the spin state of the Fe3+ cations. However, a progressive increase in the concentration of Fe4+ cations has been inferred. Relatively stronger covalent character of the Fe4+–O−2 bond causes a progressive collapse in the magnetic ordering and delocalization of the hole states.