Magnetothermal properties including magnetocaloric performance of the ternary rhombohedral Laves phase of Pr2Rh3Ge

Abstract

The article presents the study of the magnetocaloric effect (MCE) for the rhombohedral Laves phase of Pr2Rh3Ge, which shows a magnetic order below TC=8.5 K. We have established that the compound exhibits a continuous second-order type of transition which was demonstrated and confirmed by several different techniques, mainly by analyzing universal curves of normalized entropy change as a function of scaled temperature. The observed MCE, in our opinion, is a consequence of an indirect exchange coupling between the magnetic sublattices of the rare earth ions, which, however, does not exclude the potential contribution of sublattice-containing transition metals. In this paper, the procedure to evaluate the MCE from magnetization and specific heat data is described. As a result, important parameters such as the isothermal magnetic entropy change (ΔSM), adiabatic temperature change (ΔTad), relative cooling power (RCP), and the temperature averaged entropy change (TEC) were determined. The highest values of −ΔSM, ΔTad, and RCP for a field change (Δμ0H) of 5 T at TC are 5.96 J/kgK, 3.87 K, and 72.62 J/kg, respectively. These results obtained for Pr2Rh3Ge seem to be, however, low compared to the values obtained for the rhombohedral Laves phases, belonging to the group of ternary germanides RE2Rh3Ge containing heavy rare earth metals (RE = Gd, Tb, Ho, and Er). Nevertheless, we believe that the results presented in this work extend and complement the current knowledge on the magnetocaloric properties of this family of materials.