Large magnetic entropy change and refrigeration capacity around room temperature in quinary Ni41Co9-xFexMn40Sn10 alloys (x= 2.0 and 2.5)

Abstract

We report the magnetocaloric properties of two Fe-containing quinary bulk polycrystalline alloys of nominal compositions Ni41Co7Fe2Mn40Sn10 and Ni41Co6.5Fe2.5Mn40Sn10 that were determined by indirect and direct methods. Both samples showed a large refrigeration capacity RC and maximum magnetic entropy change ΔSMpeak around room temperature. For a magnetic field change of 2 T (5 T), a large magnetic entropy change of 18.9 (22.4) J kg−1 K−1 and 11.8 (16.8) J kg−1 K−1 and a refrigeration capacity of 128 (396) J kg−1 and 99 (313) J kg−1 were found in Ni41Co7Fe2Mn40Sn10 and Ni41Co6.5Fe2.5Mn40Sn10 alloys, respectively. RC for the alloy Ni41Co7Fe2Mn40Sn10, is among the largest value reported so far for Ni–Mn based Heusler alloys. Under a 1.5 T field change, the direct measurements showed the maximum adiabatic temperature changes ΔTadmax of −0.8 K and −1.5 K for these two alloys, respectively. The present findings point out the potential of Fe-alloyed Ni41Co9Mn40Sn10 Heusler alloys as room-temperature magnetic refrigerants.