Establishment of half-metallicity, ferrimagnetic ordering and double exchange interactions in Ni-doped BiFeO3 – A first-principles study

Abstract

We report the results of our first principles calculations on the effect of nickel doping on the structural, magnetic and electronic properties of BiFeO3. It is revealed from our calculations that doping of Ni into BiFeO3 lattice results in structural distortions and increases the FeOFe and OFeO bond angle. The Ni-doped BiFeO3 exhibits half-metallicity rather than the usual insulating nature of BiFeO3 due to the hybridization of both Fe and Ni 3d states with O 2p states at the Fermi level and these materials find applications in spintronics. In addition, Ni2+ establishes a ferrimagnetic exchange interaction with neighboring Fe3+ ions and the change in the magnetic state (from antiferromagnetic to ferrimagnetic) occurs. The presence of 3d electrons in the magnetically active Fe/Ni atoms leads to the existence of double exchange interactions via Fe3+O2−Ni2+ hybridization.