On the magnetism and magnetocaloric effect in PrNi2− x Co x

In search for new materials for hydrogen liquefaction through the use of the magnetocaloric effect, we investigated the PrNi2−xCox alloy series with respect to their crystallographic, magnetic, and magnetocaloric properties. This alloy series demonstrated that the substitution of nickel by cobalt leads to the emergence of ferromagnetism. The Curie temperature (Tc) ranged from 3 to 42 K for x = 0.4–2, which are ideal for magnetocaloric applications in hydrogen liquefaction. The magnetic entropy change (−ΔSM) values were found to be between 3.8 and 7.2 J/kg K for a magnetic field variation of 5 T. A Hamiltonian model, based on an effective interaction between Pr3+ and Co atoms, was used for prediction the magnetization and the magnetocaloric effect, and the results show satisfactory agreement with the experimental data.