Valence state of Mn in La_1−xSr_xMnO₃ probed by resonant Mn 3s→2p x-ray emission spectroscopy

Abstract

Mn 3s→2p x-ray emission spectrum is measured at the Mn 2p_1/2 photoabsorption maximum around 653 eV for polycrystalline La_1−xSr_xMnO₃ with x from 0 to 1. A double-peak structure like the exchange splitting in the Mn 3s core-level photoemission spectrum is observed in the Mn 3s→2p_1/2 emission spectrum. With increasing x, the splitting energy of the double-peak in the emission is nearly constant up to around x = 0.5 and then decreases until x = 1. This is consistent with the x-dependence of the Mn 3d electron number in doped manganite estimated in previous studies. It indicates that the splitting energy in the emission measures the Mn 3d spin moment or the Mn valence state of manganites. The probing depth of the method is about 100 nm.