Potential multiferroic materials of Fe-substituted BiCoO3: An ab initio study

The crystal structure, ferroelectric polarization, magnetism, and electronic structure in Fe-substituted tetragonal BiCoO3 at concentrations of 25% and 50% are investigated within the framework of density functional theory. The C-type antiferromagnetic (AFM) spin configurations with intra-layer AFM coupling interactions are energetically favorable among all the considered magnetic ordering states. Fe substitutions produce 1 μB net magnetic moment in Fe-substituted BiCoO3 system. Using the point charge model, the ferroelectric polarizations are predicted to be as high as 165 and 163 μC/cm2 for 25% and 50% Fe substitution. Electronic band structures reveal that the Fe-substituted BiCoO3 systems are ferrimagnetic insulator. Present first-principles calculation results demonstrate that Fe substitutional doping may produce multiferroic materials simultaneously showing ferrimagnetic and excellent ferroelectric properties.