Crystal and electronic structure of the composite compound Bi$_{1-x}$La$_x$Fe$_{1-y}$Mn$_y$O$_{3+\sigma}$ according to X-ray diffraction and X-ray electron spectroscopy

Based on X-ray photoelectron spectroscopy data, the ratio of the proportions of trivalent and tetravalent manganese Mn$^{3+}$/Mn$^{4+}$ in the ceramic composite compound Bi$_{1-x}$La$_x$Fe$_{1-y}$Mn$_y$O$_{3+\sigma}$ was determined. Profiles of X-ray photoelectron La$3d$-, La$4d$-, Fe$2p$- and Mn$2p$ – spectra were calculated in the isolated ion approximation, taking into account multiplet splitting in the final state of photoionization. Good agreement with experiment was obtained.