Site preference and magnetic properties of Ga/In-substituted strontium hexaferrite: An <i>ab initio</i> study

Abstract

The first-principles density functional theory has been used to study Ga/In-substituted strontium hexaferrite (SrFe12O19). Based on the calculation of the substitution energy of Ga and In in SrFe12O19 and the formation probability analysis, we conclude that in SrFe12−xGaxO19 the substituted Ga atoms prefer to occupy the 12k, 2a, and 4f1 sites, while In atoms in SrFe12−xInxO19 occupy the 12k, 4f2, and 4f1 sites. We used the site occupation probabilities to calculate the magnetic properties of the substituted SrFe12O19. It was found that as the fraction of Ga atoms in SrFe12−xGaxO19 increases, the saturation magnetization (Ms) as well as magnetic anisotropy energy (MAE) decrease, while the anisotropy field (Ha) increases. In the case of SrFe12−xInxO19, Ms, MAE, and Ha decrease with an increase of the concentration of In atoms.