The structural, electronic, magnetic, and mechanical properties of perovskite oxides PbM1/2Nb1/2O3(M = Fe, Co and Ni)

Abstract

In this study, the structural, electronic, magnetic, and mechanical properties of perovskite oxides PbM[Formula: see text]Nb[Formula: see text]O3(M = Fe, Co and Ni) are investigated. The systems are treated in ferromagnetic order. The calculations are carried out in the framework of density functional theory (DFT) within the plane-wave pseudopotential method. The exchange-correlation potential is approximated by generalized-gradient spin approach (GGA). The intra-atomic Coulomb repulsion is also taken into account in calculations (GGA + U). We have considered two generalized-gradient spin approximation functionals, which are Perdew–Burke–Ernzerhof (PBE) and PBE for solids (PBEsol) for structural parameter calculations when it included Hubbard potential. Although the spin-polarized electronic band structures of PbCo[Formula: see text]Nb[Formula: see text]O3and PbNi[Formula: see text]Nb[Formula: see text]O3systems exhibit metallic property in ferromagnetic phase, a bandgap is observed in spin-down states of PbFe[Formula: see text]Nb[Formula: see text]O3resulting in half-metallic behavior. The main reason for this behavior is attributed to the hybridization between [Formula: see text]-states of transition metal atoms and [Formula: see text]-states of oxygen atoms. The stability mechanically and the calculated mechanical properties by using elastic constants show that these compounds are mechanically stable in tetragonal phase and have anisotropic character mechanically.