Phase transition and magnetocaloric effect of Ni55.2Mn18.6Ga26.2–xGdx (x=0, 0.05, 0.15) alloys

Phase transition process and magnetic entropy change –ΔS of Ni55.2Mn18.6Ga26.2-xGdx(x=0, 0.05, 0.15) alloys were studied. Ni55.2Mn18.6Ga26.2–xGdx(x=0, 0.05, 0.15) alloys still underwent simultaneous structural and magnetic transitions and transform from ferromagnetic martensitic phase to paramagnetic austenitic phase during heating. Under a field of 2 T, the maximum magnetic entropy change –ΔSM of Ni55.2Mn18.6Ga26.15Gd0.05 alloy was 7.7 J/kg·K at 317 K during heating and 8.6 J/kg·K at 314 K during cooling while it was 11.8 J/kg·K at 317 K in Ni55.2Mn18.6Ga26.05Gd0.15 alloy during heating.