Electron- and hole-doping effects on the electronic structure of manganite studied by x-ray absorption spectroscopy

The electronic structures of hole-doped La 0.7 Ca 0.3 MnO 3 and electron-doped La 0.7 Ce 0.3 MnO 3 manganites are investigated by x-ray absorption near-edge structure spectroscopy at the O and Mn K-, and Mn L 3,2 -edges. The Mn K- and L 3,2 -edge results show that Ce dopants increase the occupation of the Mn 4p and majority-spin e g orbitals and reduce the positive effective charge of some Mn ions. However, Ce doping also induces holes in O 2p derived states. As for La 0.7 Ca 0.3 MnO 3 , in contrast to previous understanding that Ca doping converts some Mn ions into the Mn 4+ state, we find that Ca dopants actually increase the number of majority-spin e g electrons. We find instead that the holes created by Ca dopants are in the O 2p derived states.