Phase structure and magnetocaloric effect of (Tb1–xDyx)Co2 alloys

Phase structure and magnetocaloric effect of (Tb1–xDyx)Co2 alloys with x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were investigated using X-ray diffraction analysis, differential thermal analysis, and magnetization measurement. The samples were single phase with cubic MgCu2-type structure; with the increase of Dy content, TC decreased from 240 K (TbCo2) to 130 K (DyCo2), and the maximum magnetic entropy change |ΔSM,max| increased from 3.133 to 8.176 J/kg·K under low magnetic field of 0–2 T. The Arrott plot and the change of |ΔSM,max| showed that magnetic phase transition from second order to first order occured with the increase of Dy content between x=0.6 and 0.8.