Phase diagram and magnetocaloric effect in Mn2Ni1.64−xCoxSn0.36 alloys

The effect of Co substitution for Ni in Mn-rich Mn2Ni1.64−xCoxSn0.36 ferromagnetic shape memory alloys has been studied. With increasing Co content, the martensitic transformation temperatures decrease due to the decrease in valence electron concentration. The great enhancements of magnetization and Curie temperature by Co doping could be attributed to the strong Co–Mn interaction, changing Mn–Mn coupling from antiferromagnetic to ferromagnetic. In the composition range of 0.08⩽x⩽0.240.08⩽x⩽0.24, large magnetization changes and large magnetic entropy changes are observed with martensitic transformation.