Oxygen 1sx-ray-absorption near-edge structure of Zn-Ni ferrites: A comparison with the theoretical calculations

We present the electronic structure of ferrimagnetic Znₓ{Ni}_{1{{-}}x}Fe₂{O}₄$ compounds obtained by a combination of O K-edge x-ray-absorption measurements and first-principles spin-unrestricted calculations using the pseudofunction method. The two distinct preedge features are found to vary systematically as a function of the Zn content. From both experimental and theoretical analyses, we find that substitution of Ni with Zn enhances localization of the 3d states of Fe on the octahedral sites, so that the O 2p--Fe 3d hybridized states can be resolved into two distinct twofold and threefold features. {} 1996 The American Physical Society.