Effect of Mn substitution on the phase transition and magnetocaloric effect in Dy(Co1−xMnx)2 alloys

Series of Dy(Co1−xMnx)2 alloys (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) have been prepared by arc-melting method. All samples crystallize in single phase with C15 cubic MgCu2-type structure. The nature of phase transition was determined by the results of Arrott plots and Ac susceptibility, and no first order phase transition was observed for samples with x ⩾ 0.02. With the increase of Mn content, Curie temperature increases linearly, while the calculated magnetic entropy change shows an obvious decrease with a broader peak, which could be explained by the change of phase transition type.

► Curie temperature increases with the increase of Mn content.
► Arrott plots and Ac susceptibility show the disappearance of first-order magnetic transition x ⩾ 0.02.
► Large magnetic entropy change was observed for Dy(Co1−xMnx)2 with x ⩽ 0.04.