Valence states of 3d ions in lanthanum manganites-cobaltites, determined by X-ray spectroscopy

Abstract

The valence states of manganese and cobalt ions in lanthanum manganites-cobaltites La1-xCaxMn0.5 Co0.5O3 have been determined by 2p X-ray absorption and 3s X-ray photoelectron spectroscopies. The nanostructured P 1 manganite-cobaltite phase with the concentration x = 0, obtained by the citrate method at a temperature of 700°C, is characterized by a valence state of cobalt ions close to 2+ and a valence state of Mn ions of about 3.5+. The P2 phase at the same calcium concentration, synthesized by the high-temperature solid-phase method at a temperature of 1300°C, is characterized by a manganese valence of 3.5+ and a cobalt valence of about 2.3+. An increase in the dopant concentration leads to an increase in the average valence of 3d ions. © Allerton Press, Inc. 2008.