Multiplet structure for perovskite-type Ba0.9Ca0.1Ti0.9Zr0.1O3 by core–hole spectroscopies

Abstract

Core–hole spectroscopies such as x-ray photoelectron spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HR-EELS) in combination with multiplet calculation are important tools to elucidate the electronic structure of transition metal compounds. This work presents a comparison between the electronic structure obtained by XPS and HR-EELS for polycrystalline perovskite-type Ba0.9Ca0.1Ti0.9Zr0.1O3. Raman analysis suggests that Ca2+ cations could partly occupy the Ti4+ cations in the B-site of a perovskite structure with the tetragonal phase. A multiplet structure was determined by XPS for Ti 2p and by HR-EELS for Ca L2,3 and Ti L2,3 edges. Octahedral (Oh) symmetry in the crystal field (CF) effects reproduces the local distortion of TiO6 octahedra. The charge transfer (CT) effects were also considered to reproduce L3-edge EELS shoulders and the satellite in the Ti 2p XPS region. CF and CT parameters, 10 Dq, (charge transfer energy) Δ, and (Coulomb repulsion energy) Udd, are reported for future reference. The broadening of the Ti L2-edge suggests the presence of the Coster–Kronig electron decay process. Multiplet calculation in Oh symmetry for the Ca L2,3-edge could support the Raman interpretation.