Effect of Dy addition on magnetocaloric effect in PrCo₂ compound

The effect of Dy addition on the structure, magnetic and magnetocaloric properties of polycrystalline PrCo₂ compound were investigated by x-ray diffraction (XRD) and magnetic measurements. The powder XRD patterns show that all the Pr_1-xDy_xCo₂ (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) samples are linear solid solutions with C15 cubic Laves phase and MgCu₂-type structure. With the increases of Dy content, the lattice parameter decreases from 7.3090 Å for PrCo₂ to 7.1914 Å for DyCo₂, and the Curie temperature increases from 42 K (x = 0.0) to 151 K (x = 1.0). From the Arrott plots, the sample show the first order transition when 0.4 ≤ x ≤ 1.0. The magnetic entropy change of second-order PrCo₂ compound is 10.7 J kg⁻¹·K⁻¹. And the magnetic entropy change of Pr_0.6Dy_0.4Co₂ is the minimum of the whole system. After x ≥ 0.4, the magnetic entropy change value gradually increases, up to 10.4 J kg⁻¹·K⁻¹ for first-order DyCo₂ compound. The RCP of these compounds was discussed. (paper)