A comparative study of the magnetocaloric effect in Gd3Co and Gd3Ni

Magnetic and magnetocaloric properties of polycrystalline samples of Gd3Co and Gd3Ni have been studied. Both these compounds are antiferromagnets and undergo metamagnetic transitions in the antiferromagnetic phase. The Neel temperatures are found to be 128 and 99 K, respectively for Gd3Co and Gd3Ni. Though both these compounds have the same crystal structure, their magnetic structures seem to be different. It is found that Gd3Ni possesses larger magnetic anisotropy compared to Gd3Co. The maximum values of isothermal magnetic entropy change are 11 and 18.5 J Kg−1 K−1 for Gd3Co and Gd3Ni respectively, while their refrigerant capacities are 2.6 J cm−3 for both of them. Magnetic entropy change in the paramagnetic region shows a quadratic dependence on the magnetic field in the case of Gd3Ni, indicating the presence of spin fluctuations above the Neel temperature.