Magnetocaloric effect in (Er1-xGdx)Co2 pseudobinary compounds

Structure and magnetocaloric effect in (Er1-xGdx)Co2 compounds have been studied by X-ray diffraction and magnetic measurements. (Er1-xGdx)Co2 compounds have the cubic MgCu2-type structure with the lattice constant increasing linearly from 7.157Å for x=0 to 7.261Å for x=1.0. The replacement of Er by Gd enhances the Curie temperature, TC, from 32 to 403 K. The compounds exhibit large or moderate magnetocaloric effect (MCE). The value of magnetic entropy change ΔS, under an external field change of 5 T, is 15.3 J/kg K (TC=62K), 4.5  J/kg K (TC=167K) and 3.2  J/kg K (TC=296K) for x=0.1, 0.3 and 0.6, respectively. The increase in Gd content drives the magnetic transition near TC from first order to second order, thus decreasing the MCE.