Giant caloric effect of low-hysteresis metamagnetic shape memory alloys with exceptional cyclic functionality

Solid-state caloric cooling is currently under extensive study owing to its great potential to replace the conventional vapor-compression technique. The search for refrigeration materials displaying a unique combination of pronounced caloric effect, low hysteresis and high reversibility on phase transformation, as well as multiferroic behavior is nowadays very active. Here we report a singular Ni50Mn31.5In16Cu2.5 metamagnetic shape memory alloy exhibiting giant adiabatic temperature changes of 13 K upon loading and -10 K upon unloading. This value significantly exceeds any previously reported data of ferroic materials. Simultaneously, a small thermal hysteresis of 3 K and an exceptional phase transformation stability over 105 magnetic field cycles have been achieved by ensuring the compatible kinematic conditions of specific lattice interface. Moreover, we propose a strategy to further reduce hysteretic losses and improve the reversibility of magnetocaloric effect by manipulating transformation paths evoked by magnetic field and stress, and therefore such a multicaloric approach is attractively beneficial for reaching high energetic utilization efficiency. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.