Effect of Co and Cu substitution on the magnetic entropy change in Ni46Mn43Sn11 alloy

We report the observation of magnetic entropy change due to martensitic phase transformations of bulk off-stoichiometric Heusler alloys with compositions Ni46Mn43Sn11, Ni44Mn43Co2Sn11, and Ni44Mn43Cu2Sn11, prepared by arc melting method. The martensitic transition of the parent ternary alloy (Ni46Mn43Sn11) shifts to lower temperatures upon Co and Cu substitution. Inverse magnetocaloric effect was observed in these alloys near the martensitic transformation temperature when subjected to an applied magnetic field. Ni46Mn43Sn11, Ni44Mn43Co2Sn11, and Ni44Mn43 Cu2Sn11 alloys exhibited maximum positive magnetic entropy change of 7.9, 11.3, and 18.8 J kg(-1) K-1, respectively, under an applied magnetic field of 1.8 T. (C) 2011 American Institute of Physics. [doi:10.1063/1.3540327]