Nearly constant magnetic entropy change involving the enhancement of refrigerant capacity in (La0.6Ba0.2Sr0.2MnO3)1-x/(Co2O3)x composite

In this paper, we report the enhancement of the refrigerant capacity (RC) and the working temperature span (delta(TFWHM)) in (La0.6Ba0.2Sr0.2MnO3)(1-x)/(Co2O3)(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 La0.6Ba0.2Sr0.2MnO3 sample, and is depressed due to the impact of Co2O3 phase in the composites. The samples with x=0.05 and x=0.1 possess a large MCE characterized by two Delta S(T) peaks. On the other hand, the addition of 5% Co2O3 as secondary phase enhances delta(TFWHM) and RC with an increment of similar to 77.35% and similar to 14.7% respectively under a magnetic field change Delta mu H-0 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. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.