Electronic Structures of La[sub 0.7]Ca[sub 0.3]MnO[sub 3] and La[sub 0.7]Ce[sub 0.3]MnO[sub 3] by X-Ray Absorption Spectroscopy.

Electronic structures of hole-doped and electron hole-doped manganites, La[sub 0.7]Ca[sub 0.3]MnO[sub 3] and La[sub 0.7]Ce[sub 0.3]MnO[sub 3], have been elucidated by X-ray absorption near-edge structure (XANES) spectra of O K- and Mn L[sub 3,2]-edges. In the electron-doped system, La[sub 0.7]Ce[sub 0.3]MnO[sub 3], the spectral features of O K-edge spectra are shifted by ∼ 1 eV towards the higher energy side and reduction of Mn valency from 4[sup +] and 3[sup +] to 3[sup +] and 2[sup +] is expected when compared to hole-doped manganite. The XANES of Ce M[sub 5,4]-edges indicates a tetravalent state for Ce, similar to that in CeO[sub 2]. Ce[sup 4+] is incorporated into the lattice of LaMnO[sub 3], resulting in the modification of MnO[sub 6] octahedra and also indicating strong hybridization of Ce 5d and/or Ce 4f states with O 2p states. [ABSTRACT FROM AUTHOR]