X-ray photoelectron study of the valence state of iron in iron-containing single-crystal (BiFeO3, PbFe1/2Nb1/2O3), and ceramic (BaFe1/2Nb1/2O3) multiferroics

▶ Fe2p, Fe3p, and Fe3s XPS in single-crystal BiFeO3 and PbFe1/2Nb1/2O3, are measured. ▶ Single-crystal multiferroics and Fe2O3 have the Fe ions only in the Fe3+ valence state. ▶ BaFe1/2Nb1/2O3 ceramic samples with various Fe2+/Fe3+ abundances are synthesized. ▶ An approximate method to determine the Fe2+/Fe3+ abundances is suggested.