Electronic structure and magnetic properties of PbMO3 (M = Fe, Co, Ni) magnetic perovskites: An ab initio study

We present the electronic, magnetic and structural properties of the magnetic transition metal oxides PbMO3 (M= Fe, Co, Ni) in cubic perovskite structure. The calculations are based on the density functional theory (DFT) within plane-wave pseudopotential method and local spin density approximation (LSDA) of the exchange-correlation functional. Onsite Coulomb interaction is also included in calculations (LSDA + U). The systems are considered in ferromagnetic (FM) and G-type antiferromagnetic (G-AFM) order. FM structures are energetically more favored than G-AFM and than non-magnetic states for all the systems studied. The spin-polarized electronic band structures show that all the structures have metallic property in FM order without Hubbard-U interaction (U-eff = 0). However, the inclusion of on-site Coulomb interaction (U-eff = 7 eV) opens a semiconducting gap for majority spin channel of PbFeO3 and of PbNiO3 resulting in a half-metallic character. PbCoO3 system remains as metallic with LSDA + U scheme. Bonding features of all structures are largely determined by the hybridizations between O-p and d-states of transition metal atoms. The partial magnetic moment of Fe atom in PbFeO3 is enhanced by inclusion of Hubbard-U interaction (2.55 mu B double right arrow 3.78 mu B). Total magnetic moments of half-metallic PbFeO3 and of PbNiO3 compounds are very close to integer values.