Reversible magnetic-field-induced martensitic transformation over a wide temperature window in Ni_42−xCo_xCu₈Mn₃₇Ga₁₃ alloys

Ni_42−xCo_xCu₈Mn₃₇Ga₁₃ (0 ≤ x ≤ 14) alloys are reported to exhibit a magnetostructural transition from weakly-magnetic martensite to ferromagnetic austenite over a rather wide temperature window ranging from 200 K to 380 K. Simultaneously a large magnetization change Δσ of up to 105 Am² kg⁻¹ is obtained at the martensitic transformation. A reversible magnetic-field-induced martensitic transformation is realized, resulting in a large magnetocaloric effect related to the high magnetic entropy change with a broad working temperature span. This work shows how it is possible to effectively tailor the magnetostructural transition in Ni-Mn-Ga alloys so as to achieve a reversible magnetic-field-induced martensitic transformation and associated functionalities.