The effect of Co substitution on the magnetic and magnetocaloric properties of Gd3Ru

The effects of Co substitution on the structure, magnetic properties, and magnetocaloric effect of Gd3Ru1−xCox (0.05 ≤ x ≤ 0.20) alloys have been investigated by X-ray diffraction and magnetization measurements. The Curie temperatures varied between 60 K and 92 K with Co substitution for Ru. With an applied magnetic field change (ΔH) of 50 kOe, the maximum values of magnetic entropy change (−ΔSM) were determined to be 25.8, 23.1, 19.4, and 10.8 J/kg K for compositions with x = 0.05, 0.10, 0.15, and 0.20, respectively. The corresponding refrigeration capacities (RCs) for the alloys were reasonably large and calculated to be 495, 475, 467, and 517 J/kg. The magnetic phase transitions in the Gd3Ru1−xCox (0.05 ≤ x ≤ 0.15) alloys are of first-order. In the Gd3Ru0.80Co0.20, the first-order magnetic phase transition disappears and the transition is broadened hence it increases in RC. The high −ΔSM values and accompanying large RCs for the Gd3Ru1−xCox (0.05 ≤ x ≤ 0.20) alloys qualify them as potential candidates for magnetic refrigeration applications near liquid nitrogen temperature.