First principles study of magnetic properties of Zn-Sn substituted M-type Sr-hexaferrite

Site occupancy and magnetic properties of Zn-Sn substituted M-type Sr-hexaferrite SrFe_12-x(Zn_0.5Sn_0.5)_xO₁₉ with x=1 were studied using density functional theory and generalized gradient approximation (GGA). Using the GGA+U method the description of strongly correlated 3d electrons of Fe was improved. Our results show that Zn and Sn atoms prefer to occupy 4f₁ and 4f₂ sites respectively. Favorable Zn-Sn substituted configurations show an increase in saturation of magnetization (M_s), and a decrease in magnetic anisotropy energy (MAE), over the pure M-type Sr-hexaferrite (x=0). Experimental observations agree with the decrease of MAE and the increase of M_s for Zn-Sn substituted Sr-hexaferrite.