Effect of local coordination of Mn on Mn-L2,3 edge electron energy loss spectrum

Abstract

The effects of the local coordination environment of Mn ions in perovskite manganese oxides on the Mn-L2,3 edge electron energy loss (EEL) spectra was experimentally and theoretically investigated. The Mn-L2,3 edge EEL spectra were observed for various perovskite manganese oxides, including YMnO3, LaMnO3, BaMnO3, SrMnO3, and CaMnO3, in which the Mn ions have different valence states and local coordination. The experiment revealed that the Mn L3/L2 ratio is influenced not only by the valence state but also by the local environment of the Mn ions. Furthermore, compared to the Mn L3/L2 ratios of Mn3+ compounds, the Mn L3/L2 ratios of the Mn4+ compounds are found to be much more sensitive to local distortions. The ab-initio multiplet calculation of the Mn-L2,3 edge EEL spectra revealed that the effects of local coordination on the spectral features are dependent on the local electronic structures of the Mn ions. These findings indicate that the valence state as well as the local environments of the Mn ions can be unraveled by combining experimental and theoretical investigations of Mn-L2,3 edge EEL spectra.