Phase transition and magnetocaloric effect of Ni50Mn29Ga21-xTbx (0 ≤ x ≤ 1) alloys

Ni50Mn29Ga21 Tb-x(x) (0 <= x <= 1) alloys were studied with the microstructure, phase transition, and magnetocaloric effect. Dual-phase microstructure containing the martensite matrix and Tb-rich precipitations were formed. The martensitic transformation was observed over the whole composition range, with the transformation temperature T-M significantly increased by the addition of terbium. The magnetic transition temperatures of the austenite and martensite, i.e. T-C(A) and T-C(M), were monitored for 0 <= x <= 0.16 and 0.27 <= x <= 1, respectively. Both T-C(A) and T-C(M) were slightly decreased by the addition of terbium. For 0.16 <= x <= 0.27 the martensitic transformation was coincided with the magnetic transition in case of T-M = T-C, giving rise to the coupled magneto-structural transition from ferromagnetic martensite to paramagnetic austenite. Sizable magnetic entropy change was induced by magnetic field in the vicinity of the coupled magneto-structural transition. (C) 2015 Elsevier B.V. All rights reserved.