Electron energy loss spectroscopy in ACrO3 (A = Ca, Sr and Pb) perovskites

Abstract

We present the experimental ELNES spectra of the Cr-L2,3 and O-K edges in three high pressure synthesized perovskites, ACrO3 (A = Ca, Sr and Pb). A comparison of the experimental spectra against the theoretical calculations shows the influence of the A cation in the features of the spectrum. The Cr-L2,3 multiplet structure of these perovskites shows similar integrated intensity ratio (IL3/IL2) between them and with the CrO2, implying that all of them are indeed composed by Cr4+. But the O-K pre-edge observed in CrO2, typical of its d3L character (L-ligand hole), is not present in these perovskites. The effect of the A cation manifests itself in the O-K edge. The different features in the peak edges are caused by the change in the interaction between oxygen and the A cation from being via p orbitals (with Pb) to being via d orbitals (with Ca, Sr). The experimental spectra of the samples are reproduced well by the presented DFT calculations.