Multiplicity of Zn coordination sites at cubic spinel ferrites: magnetism and influence of the Zn d band

Abstract Zinc substituted nickel ferrite (Zn x Ni 1 − Fe 2 O 4 ) is investigated under density functional theory (DFT) within the DFT + U approximation for ≤ 0.50, with particular interest in understanding effect of Zn on net magnetization. Using as a reference ZnFe , localization d band proved to have large impact preference occupy either tetrahedral A or octahedral B coordination sites, which equivalent relative stability direct and inverse spinel forms. This affects lattice volume, favoring larger expansions. Additional important consequences emerge magnetism system, alter balance atoms at magnetic sublattices different way: while enhances global magnetization by reducing minority spin contribution, opposite occurs . On other hand, dominant exchange interactions are not significantly altered independently its distribution, anisotropy soft NiFe further weakened. Our simulations support presence significant ratio positions mainly concentration increases, putting limits ability increase substitution.