Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistive manganiteLa0.7Ce0.3MnO3films

The electronic structure of ${\mathrm{La}}_{0.7}{\mathrm{Ce}}_{0.3}{\mathrm{MnO}}_3$ (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 ${\mathrm{CeO}}_2,$ indicating that Ce ions are close to being tetravalent. A very weak $4f$ resonance is observed around the Ce $4\overrightarrow{d}4f$ 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 ${\mathrm{Mn}}^{2+}$ multiplet feature, confirming the ${\mathrm{Mn}}^{2+}-{\mathrm{Mn}}^{3+}$ 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 $\mathrm{LSDA}+U$ (LSDA, local spin-density approximation) method. The $\mathrm{LSDA}+U$ calculation predicts a half-metallic ground state for LCeMO. This study confirms that the LCeMO films are indeed electron doped.