Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistive manganite La_0.7Ce_0.3MnO₃ films

Abstract

The electronic structure of La_0.7Ce_0.3MnO₃ (LCeMO) thin films has been investigated using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The Ce 3d core-level PES and XAS spectra of LCeMO are very similar to those of CeO₂, indicating that Ce ions are close to being tetravalent. A very weak 4f resonance is observed around the Ce 4→d4f absorption edge, suggesting that the localized Ce 4f states are almost empty in the ground state. The Mn 2p XAS spectrum reveals the existence of the Mn²⁺ multiplet feature, confirming the Mn²⁺−Mn³⁺ mixed-valent states of Mn ions in LCeMO. The measured Mn 3d PES/XAS spectra for LCeMO agree reasonably well with the Mn 3d partial density of states calculated using the LSDA+U (LSDA, local spin-density approximation) method. The LSDA+U calculation predicts a half-metallic ground state for LCeMO. This study confirms that the LCeMO films are indeed electron doped.