Jahn-Teller effect in spinel manganites probed by soft x-ray absorption spectroscopy

Abstract

We present soft x-ray absorption spectroscopy (XAS) on spinel manganites and show it can be used as a powerful tool to directly probe the Jahn-Teller (JT) splitting energy in transition metal oxides. The MnL2,3-edge XAS spectra of the spinel ZnMnxGa2−xO4(x=0.5,1.0,1.4,and2.0) and AMn2O4(A=MgandCd) change very systematically with the structural distortion of JT active octahedral sublattices. The XAS spectra are well reproduced by the configuration interaction cluster model including full ionic multiplet structure, and the spectral evolution is explained by JT energy splitting due to the elongation of the MnO6 octahedra in the model. In the OK-edge XAS spectra, the JT distortion produces a weak effect, less distinctive than in L2,3-edge spectra.