up to 20-times larger cooling powers per mass compared to gadolinium (Gd), a benchmark magnetocaloric material, with comparable coeffi cient-of-performance (COP) values (≈5).These results can open up a new way of making cooling devices with much more compact systems and with the possibility of avoiding expensive rare-earth materials.The martensitic transformation is a fi rst-order solid-tosolid diffusionless structural transformation responsible for the shape memory effect and superelasticity. [ 23 ] When a shape memory alloy in the austenitic (cubic) phase is axially stressed, an exothermic austenitic-martensitic transformation occurs, which under adiabatic conditions causes the material to heat up. This heated material then rejects heat to the surroundings and cools down to the ambient temperature. When the stress is removed, the crystal structure transforms back to the austenitic phase, the material cools down and is now able to absorb heat from the surroundings. This process (as a cooling cycle) is schematically shown in Figure 1 a. In general, the main groups of superelastic alloys are Ni-Ti-based (doped with Cu, Co, Pd, etc.); Cu-based (doped with Al, Ni, Zn, Mn, etc.), and Fe-based (doped with Pd, Rh, Mn, Si, Ni, etc.) alloys. [ 23 ] All of those alloys can also be considered as potential elastocaloric materials when they undergo stress-induced transformation and its transfor-