Soft x-ray absorption spectroscopy and magnetic circular dichroism study of the valence and spin states in spinel MnFe2O4

Abstract

The valence and spin states of MnFe(2)O(4) spinel oxide have been investigated by employing soft x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). The measured Mn 2p and Fe 2p XAS spectra indicate that Mn and Fe ions are nearly divalent (Mn(2+)) and trivalent (Fe(3+)), respectively. Our XAS and XMCD spectra for MnFe(2)O(4) do not show clear evidence of mixed-valent states but provide evidence for the inversion of both Mn and Fe ions, with T(d)/O(h)similar to 0.8/0.2 for Mn ions and T(d)/O(h)similar to 0.1/0.9 for Fe ions, respectively. Based on our data, MnFe(2)O(4) can be described either by the single-valence states of (Mn(0.8)(2+)Fe(0.2)(3+))(A)[Fe(1.8)(3+)Mn(0.2)(2+)](B)O(4) or by the mixed-valence states of (Mn(0.8)(2+)Fe(0.2)(3+))(A)[Fe(1.6)(3+)Fe(0.2)(2+)Mn(0.2)(3+)](B)O(4).