Ce Electronic States In Nd0.45-Xcexsr0.55mno3 Probed By X-Ray Absorption Spectroscopy And Photoemission

We have investigated the Ce 4f electronic states in the Ce-doped manganites Nd0.45-xCexSr0.55MnO3 (NCSMO) by means of x-ray absorption spectroscopy (XAS) and hard x-ray photoelectron spectroscopy (HAXPES). The Ce 3d XAS shows that the Ce ions exist in the form of the Ce3+ and Ce4+ mixed-valent states, and we have found that the XAS spectral features change with temperature. The Ce 3d XAS and HAXPES spectra for NCSMO agree reasonably well with calculated results based on the single-impurity Anderson model, which takes into account the atomic multiplets and two valence bands. The estimated Ce bulk valence of Nd0.15Ce0.3Sr0.55MnO3 decreases from 3.44 to 3.30 with cooling.