Multiferroic and half-metallic character of hexagonal BaTi0.5Fe0.5O3: DFT based calculation

ABSTRACT In this paper, we report a density functional theory (DFT) calculation study based on the full potential linear augmented plane wave (FP-LAPW) to investigate the effect of Fe incorporation in hexagonal BaTiO3 with a high Fe content : BaTi0.5Fe0.5O3.We discuss the structural, mechanical, electronic and magnetic properties as well as the spontaneous electrical polarisation P. The partial Fe substitution in BaTiO3 conserves and doubles its initial polarisation value from 0.12 to 0.25 C/m2. In contrast to nonmagnetic BaTiO3, we observe a net magnetic moment of 6.0 μB/formula unit. But, when the strong correlations among d electrons of Fe atoms are taken into account, the total magnetic is increasing and is equal to 10 μB/formula unit, due to a net increasing of magnetic moment of Fe atoms. Therefore, the coexistence of spontaneous electrical polarisation P along with a magnetic moment leads to a new and interesting multiferroic behaviour. We also observe a half-metallic behaviour in which spin down bands structure shows metallic character whereas spin up bands structure shows semi-conductor character with an energy gap of 1.48 eV. This reveals that the multiferroic BaTi0.5Fe0.5O3 could be potential candidate for spintronics devices.