Cyclic reversible martensitic transformation and magnetocaloric effect in a Ni51.0Mn20.8Ga22.4Cu5.8 alloy

•A Ni51.0Mn20.8Ga22.4Cu5.8 alloy was subjected to 50 thermal and magnetic cycles.•The martensitic transformation exhibits small hystereses and excellent reversibility.•The martensite/austenite transferring interface is geometric compatible.•A reversible magnetic entropy change of up to 21.7 J/kgK is achieved under 50 kOe. Working materials exhibiting a large reversible magnetocaloric effect are necessary for improving the cooling efficiency of magnetic refrigeration. Herein, the cyclic reversibility of the martensitic transformation and magnetocaloric effect in a Ni51.0Mn20.8Ga22.4Cu5.8 alloy is investigated. The martensitic transformation exhibits small thermal and magnetic hystereses (∼6 K and ∼6.8 J/kg, respectively) and excellent reversibility upon 50 thermal and magnetic cycles owing to the good geometric compatibility of the martensite/austenite transferring interface. A reversible magnetic entropy change up to −21.7 J/kgK is achieved under 50 kOe after performing 50 magnetic cycles, indicating the excellent reversibility of the magnetocaloric effect in the alloy.