Electron-energy-loss core-edge structures in manganese oxides

Abstract

Oxygen K and manganese ${\mathit{L}}_{2,3}$ edges electron-energy-loss spectra have been measured for a series of manganese oxides with different nominal oxidation states for the cation (MnO, ${\mathrm{Mn}}_{3}$${\mathrm{O}}_{4}$, ${\mathrm{Mn}}_{2}$${\mathrm{O}}_{3}$, ${\mathrm{MnO}}_{2}$, and ${\mathrm{BaMnO}}_{4}$). Spectra have been processed for quantitative elemental analysis and for the evaluation of manganese ${\mathit{L}}_{2,3}$ white-line intensity ratios and normalized total intensities. Prepeaks on the oxygen K edge are sensitive to the nature of local chemical bonds and their detailed substructures are interpreted with the support of a molecular-orbital picture. As for the cation point of view, the analysis of the white-line intensities provides a satisfactory measurement of the effective 3d orbital occupancy as well as a hint of the local magnetic properties. The present study also confirms that the hybridization between oxygen 2p and manganese 3d orbitals plays an important role when considering the electronic structures of these oxides.