Study of the electron structure of Mn, Sr, La, Ce, and Sm cations in Ln1 − x Sr x MnO3 (Ln = La, Ce, Sm) manganites by the X-ray line shift method

Abstract

The X-RayKα line shifts of all cations in Ln1 − xSrxMnO3 (Ln = La, Ce, Sm) manganites have been measured using crystal diffraction spectrometers. The Mn Kαline shifts have been found in the Sm1 − xSrxMnO3 system correspond to an increase in the valence from Mn3+ to Mn4+. In the Ce1 − xSrxMnO3 system, in addition to this, the valence of cerium have been found also increases to almost 4. It is shown that the dependence of the valence of manganese on the content of strontium does not correspond to a simple model of the local mixture of Mn3+ and Mn4+ ions, which is usually applied to these systems. It is also demonstrated that the bonds of Sr, La, and Sm in the manganites studied exhibit a significant covalent character. In cation-deficient Sm1 − yMn1 − zO3, an increase in the valence of Mn is found accompanied by a decrease in the covalence of Sm.