Enhancement of refrigeration capacity and table-like magnetocaloric effect in La0.8Ca0.2MnO3/La0.8K0.2MnO3 nanocrystalline composite

Abstract

In this paper we report on the magnetocaloric effect and refrigeration capacity (RC) of La0.8Ca0.2MnO3(LCMO)/La0.8K0.2MnO3(LKMO) composite with a mass fraction of 1:1. X-ray diffraction patterns indicate that the component manganites crystalize in the same rhombohedral structure. The LCMO and LKMO undergo second-order phase transitions at 247K and 281K, respectively. The maximum values of isothermal entropy change (−ΔST,max) are found to be 4.25J/kgK and 3.71J/kgK under a magnetic field change of 5T for LCMO and LKMO, respectively. The composite exhibits a table-like ΔST curve with slightly lowered peak value. An enhancement of 33%–35% for RC has been found in the composite when comparing with those of the components. It reveals that the combination of magnetocaloric materials with different Curie temperatures is a possible method for improving RC.