(La,Sr)(Mn,Me)O3 manganites doped with d metals: Study of charge compensation mechanisms by crystallographic and magnetic characterizations

A comparison between theoretically calculated unit cell volume and interatomic distances in the system La0.7Sr0.3Mn1−xMexO3+δ (where Me = Cu, Fe, Cr, Ti) and the experimental data obtained by the full-profile Rietveld X-ray analysis as well as an analysis of magnetic properties allowed us to suggest possible mechanisms of charge compensation occurring when d metals substitute for manganese. It has been shown that in the case when copper, iron, chromium and titanium ions substitute for manganese ions in the system La0.7Sr0.3Mn1−xMexO3 charge compensation is described by the model 2Mn3+ → Mn4+ + Cu2+, Mn3+ → Fe3+, Mn3+ → Cr3+ and Mn4+ → Ti4+, respectively. In the latter case, a decrease in oxygen nonstoichiometry occurs with increasing x.