Electron- and Hole-Doping Effects in Manganites Studied by X-Ray Absorption Spectroscopy

Abstract

We investigate the electronic structures of hole-doped, La 0.7 Ca 0.3 MnO 3 , and electrondoped, La 0.7 Ce 0.3 MnO 3 , manganites by x-ray absorption near edge structure (XANES) spectroscopy at the O and Mn K-edges. While, the O K-edge XANES results indicate that Ca and Ce doping induce holes in O 2p derived states, the Mn K-edge XANES do not give any evidence for creation of the Mn 4+ (or Mn 2+ ) ions by Ca (or Ce) dopants. Such results further questions the validity of double exchange mechanism in understanding the anomalous properties of manganites.