Effect of A-site-substitution on structural, magnetic and magnetocaloric properties in La0.7Sr0.3 Mn0.9Cu0.1O3 manganite

Abstract

Abstract The effect of bismuth and calcium substitution on the structure, magnetic and magnetocaloric properties in La0.7Sr0.3Mn0.9Cu0.1O3 manganite compounds were investigated. All the samples were synthesized using the conventional sol-gel route. The structural analysis revealed that our compounds crystalize in the rhombohedral structure ( R 3 - c space group), at room temperature. The magnetic measurements showed that all the studied compounds exhibited a second order paramagnetic (PM)-ferromagnetic (FM) transition at Curie temperature TC ranging between 290 and 320 K. The magnetic entropy change ( - Δ S M ) values estimated by the Landau theory are very close to those obtained using the classical Maxwell relation. Under an applied field μ0H = 5 T, the maximum of the magnetic entropy change ( - Δ S M max ) and the relative cooling power (RCP) are found to be 3.06 J/kg.K and 198 J/kg for La0.7Sr0.3Mn0.9Cu0.1O3, 3.39 J/kg.K and 161 J/kg for La0.6Bi0.1Sr0.3Mn0.9Cu0.1O3, and 3.65 J/kg.K and 184 J/kg for La0.6Bi0.1Sr0.25Ca0.05Mn0.9Cu0.1O3. These obtained values were compared with those of some other reported manganite and showed that our compounds could be as promising candidates for magnetic refrigeration.