Mixed valence manganites; magnetic manganites; magnetocaloric effect; Pechini method.
Polycrystalline manganites of composition La2/3Sr1/3Mn1−𝑥T𝑥O3 (T = Cr3+ or Fe3+, x = 0.0-0.10) were obtained by the Pechini method. Their magnetic properties exhibited a marked dependence on Fe/Cr content, with significant reduction of the magnetic moment per formula unit and their Curie temperatures. In addition, the magnetocaloric effect, determined by isothermal magnetization measurements, displayed a decreasing tendency with increasing Fe/Cr concentration. Results were interpreted on the basis of a deleterious effect on the double exchange interaction provoked by the presence of Fe3+ and Cr3+ ions within the crystal structure.