Excellent magnetocaloric properties of La_(0.7)Ca_(0.3-x)Sr_xMnO_3 (0.05≤x≤0.25) single crystals

摘要

This letter reports on the superior magnetocaloric properties of La_(0.7)Ca_(0.3-x)Sr_xMnO_3 (x=0.05, 0.10, 0.20, and 0.25) single crystals. Upon 50 kOe applied field, the magnetic entropy changes (ΔS_M) reach values of ～10.5, 7.45, 6.97, and 6.86 J/kg K for x=0.05, 0.10, 0.20, and 0.25 compositions, respectively. The large magnetic entropy changes have been found to occur around 300 K, thus allowing magnetic refrigeration at room temperature. Due to the absence of grains in the single crystals, the ΔS_M distribution here is much more uniform than that of gadolinium and polycrystalline manganites, which is desirable for an Ericson-cycle magnetic refrigerator. The single crystals have the large magnetic entropy changes induced by low magnetic field change, which is beneficial for the household application of active magnetic refrigerant (AMR) materials. These results indicate that the present single crystals are excellent candidates as working materials for AMR.