Broad refrigeration temperature window associated with multicaloric effects in Ni-Mn-Sn-Cu-B alloys

Abstract

Ni-Mn-Sn-based magnetic shape memory alloys (MSMAs) exhibit multifunctional properties such as elastocaloric effect (eCE) and magnetocaloric effect (MCE). The (Ni<inf>47</inf>Mn<inf>38</inf>Sn<inf>12</inf>Cu<inf>3</inf>)<inf>99.4</inf>B<inf>0.6</inf> alloy with the magnetic entropy change (ΔS<inf>m</inf>) of 21.2 J/kg·K at near-room-temperature is reported, under a magnetic field of 5 T. Remarkably, a large reversible eCE is achieved, with a directly measured adiabatic temperature change (ΔT<inf>ad</inf>) reaching up to 10.3 K. Throughout 200 loading–unloading cycles, the eCE shows excellent cyclic stability with no discernible decline. Moreover, the multicaloric effects resulting from the simultaneously applied uniaxial stress and magnetic field in the “blank region” between the magnetocaloric and elastocaloric operating temperature regions are analyzed and experimentally verified. Under the combination of MCE and eCE, the working temperature window could be largely broadened and cover the temperature range of 260 K to 336 K. Hydrostatic pressure coupled with a magnetic field increases the refrigeration capacity by 22%. The design of refrigeration materials with reversible large caloric effects, considerable cycle stability, and a broad refrigeration temperature range may benefit from the findings of this work.