Valence state and X-ray photoelectron 2p spectra of chromium ions in the La1–xSrxCrO3 (x = 0, 0.1, 0.3, 0.5) system

Resumo

Room-temperature Cr2p X-ray photoelectron spectra of samples of the La_1–xSr_xCrO₃ system with x = 0, 0.1, 0.3, and 0.5 are obtained. The profiles of these spectra vary considerably with x. XPS analysis shows that the chromium ions are in a mixed valence state. The introduction of Sr²⁺ ions into the lattice is compensated for by the mechanism of Cr³⁺, Cr⁴⁺, Cr⁵⁺, and Cr⁶⁺ ion formation. Decomposition of Cr2p_3/2 spectra into components with profiles corresponding to Cr³⁺, Cr⁴⁺, Cr⁵⁺, and Cr⁶⁺ ions has shown that the contribution from Cr6+ ions grows along with with x in the Cr2p_3/2 spectra, while the contribution from Cr³⁺, Cr⁴⁺, and Cr⁵⁺ ions is reduced at higher x values.