Effect of Cr Substitution on Magnetic and Magnetocaloric Properties for La0.62Nd0.05Ba0.33MnO3

In this paper, we investigate the structural, magnetic, and magnetocaloric properties of La 0.62 Nd 0.05 Ba 0.33 Mn 1- x Cr x O 3 manganites elaborated by sol gel process. X-ray diffraction analyses confirm that all elaborated samples are crystallized on the rhombohedral perovskite structure with R-3c space group. Magnetic measurements reveal the presence of a magnetic transition from paramagnetic ( PM ) to ferromagnetic ( FM ) phase in the vicinity of Curie temperature T C . However, as Cr concentration increases, we witness a decrease in T C from 285 K for x = 0 to 250 K for x = 0.20. This behavior can be explained by the double exchange interaction of Mn 3+ -O-Mn 4+ . The maximum entropy change ( - Δ S m max ) at µ 0 H = 5 T is found to be 2.63, 1.88, and 1.76 J.kg −1 .K −1 for x = 0, 0.10, and 0.20, respectively. However, our research underlines the enhancement of relative cooling power ( RCP ) by Cr doping, from 310 to 340 J.kg −1 as Cr concentration increases from x = 0 to 0.20. This finding suggests the usefulness of our samples as magnetic refrigeration material around room temperature. Furthermore, the analysis of the magnetocaloric effect ( MCE ) using the Landau theory shows a good agreement with the experimental results with a soft difference, indicating the importance of Jahn–Teller interactions on manganites perovskite.