Influence of atomic ordering on elastocaloric and magnetocaloric effects of a Ni–Cu–Mn–Ga ferromagnetic shape memory alloy

Highlights: • Ni₅₁Cu₄Mn₂₀Ga₂₅ alloy exhibits normal elastocaloric and magnetocaloric effects. • L2₁ atomic order of the alloy is increased after annealing at 773 K for 10 h. • Increasing L2₁ atomic order improves its elastocaloric and magnetocaloric effects. • Atomic ordering modifies the magnetic and martensitic transitions of the system. - Abstract: The coexisting elastocaloric and magnetocaloric effects in ferromagnetic shape memory alloys have attracted much attention for the potential application in solid state refrigeration. Previous studies show that the L2₁ atomic ordering of Heusler ferromagnetic shape memory alloys plays important role on their magnetocaloric effect. However, no research work investigates the effect of atomic ordering on their elastocaloric effect yet. In this study, we investigated the influence of atomic ordering on the elastocaloric and magnetocaloric effects of a Ni₅₁Cu₄Mn₂₀Ga₂₅ ferromagnetic shape memory alloy. The alloy exhibits normal elastocaloric effect and normal magnetocaloric effect near room temperature. Moreover, we found that the enhancement of atomic order in this alloy can greatly increase the entropy change and refrigeration capacity of its elastocaloric and magnetocaloric effects. This is attributed to that the atomic ordering modifies the magnetic and martensitic transitions of the system