Electronic structure of NaNbO3–Mn single crystals

The XPS spectra of the NaNbO3 single crystals doped with manganese (x=0.1, 0.5, 1.0, 3.0, 5.0 and 10.0%) were measured using the PHI 5700/660 physical electronics photoelectron spectrometer at room temperature within the antiferroelectric phase. From the spectra the atomic concentration was calculated and compared to the nominal composition. The approximate solubility limit of the Mn ions, built into the sodium niobate crystal lattice, was determined as 1.0% Mn. The dependence of the core level peak position and valence band on manganese dopant was determined. The influence of sputtering with the Ar+ ions on the Nb core line and valence band shape was observed. This effect was ascribed to the change in niobium valence due to the oxygen defects produced during the sputtering process.