Valence states and occupation sites in(Fe,Mn)3O4 spinel oxides investigated by soft x-ray absorption spectroscopy and magnetic circulardichroism

Abstract

The electronic structures of (Fe,Mn)3O4 spinel oxides have been investigated by employing soft-x-ray absorptionspectroscopy (XAS) and soft x-ray magnetic circular dichroism (XMCD). We havedetermined the valence states as well as the occupation sites of Mn and Fe ions inFe0.9Mn2.1O4 and MnFe2O4. Fe0.9Mn2.1O4 is found to be close to the inverse spinel (the inversion parametery≈0.85), whileMnFe2O4 is close to thenormal spinel (y≈0.2). In Fe0.9Mn2.1O4, Fe ions are mainly trivalent and the majority ofFe3+ ions occupy the octahedral B sites, while Mn ions are mixed-valent with approximately 45%MnA2+ at the tetrahedral Asites and 55% MnB3+ ions atthe octahedral B sites. In MnFe2O4, Mn ions are mainly divalent and the majority ofMn2+ ions occupy the tetrahedral A sites, while Fe ions are mainly trivalent and the majority ofFe3+ ions occupy the octahedral B sites.