Magnetocaloric effect of La0.7−xPrxCa0.3MnO3 perovskites

The magnetic properties and the magnetocaloric effect (MCE) of La0.7−xPrxCa0.3MnO3 perovskite materials (0 ⩽ x ⩽ 0.69) were investigated. Magnetic entropy changes (ΔSM) were calculated both from magnetization data using Maxwell’s relation and specific heat data. With increasing x, the Curie temperature TC decreases from 240 to 119 K. The maximum value of ΔSM, the adiabatic temperature change (ΔTad), and the relative cooling power (RCP) induced by demagnetization from 1 to 0 T were 6.8 J/kg K, 2.5 K, and 54 J/kg at 225 K, for x = 0.1. These parameters were about 200%, 80%, and 65% of the comparable Gd parameters, indicating that these materials are promising candidates as magnetic refrigerants in the sub-room temperature range (200–250 K).

► La0.7−xPrxCa0.3MnO3 with orthorhombic crystal structure were synthesized.
► Samples for x ⩽ 0.32 show first-order transition materials.
► An x = 0.13 sample has the maximum magnetocaloric effect.
► ΔSM tends to increase with increasing unit cell volume.