Nearly constant magnetic entropy change involving the enhancement of refrigerant capacity in (La 0.6 Ba 0.2 Sr 0.2 MnO 3 ) 1−x /(Co 2 O 3 ) x composite

Abstract In this paper, we report the enhancement of the refrigerant capacity (RC) and the working temperature span ( δ TFWHM ) in (La 0.6 Ba 0.2 Sr 0.2 MnO 3 ) 1− x /(Co 2 O 3 ) x composite. The composite samples with nominal compositions were prepared using the conventional solid-state reaction method. Magnetization measurements reveal that the composite exhibits two successive second-order ferromagnetic-like transitions at T C1 and T C2 for x =0.05 and x =0.1 with decreasing temperature. T C1 remains almost constant with increasing x , but T C2 shifts significantly to lower temperature. A large magnetic entropy change is observed in La 0.6 Ba 0.2 Sr 0.2 MnO 3 sample, and is depressed due to the impact of Co 2 O 3 phase in the composites. The samples with x =0.05 and x =0.1 possess a large MCE characterized by two Δ S ( T ) peaks. On the other hand, the addition of 5% Co 2 O 3 as secondary phase enhances δ TFWHM and RC with an increment of ~77.35% and ~14.7% respectively under a magnetic field change Δ μ 0 H of 4.5 T compared with the parent compound. These composites can be used as the working material in the Ericsson-cycle magnetic regenerative refrigerator. Our findings constitute a good starting point to stimulate the search for new composites with enhanced MCE properties around room temperature range.