Magnetocaloric effect of Ce(La)In2 alloys near hydrogen condensation point

Gas liquefiers allow efficient transport and storage of gases, key for the development of new energy vectors such as hydrogen fuel. In this sense, magnetic liquefiers based on the magnetocaloric effect are an energy-saving and sustainable alternative to current systems based on the Joule-Thomson expansion. Here, we report the magnetocaloric effect of light rare-earth-based Ce(La)In 2 alloys near the hydrogen condensation point. They exhibit a first-order ferromagnetic to paramagnetic phase transition with reduced thermal hysteresis (0.05 K) and moderate criticality compared to their heavy rare-earth-based counterparts. Both isothermal entropy change, and adiabatic entropy change have been indirectly determined from heat capacity measurements. A previously developed method based on low-temperature truncation of heat capacity data was applied for those calculations, accounting for 8% underestimation of the maximum values as well as possible misinterpretations of the results in the paramagnetic range. The parent CeIn 2 alloy shows an isothermal entropy change of 9.5 J/(kg∙K) and an adiabatic temperature change of 2.8 K for a magnetic field change of 5 T. The substitution of Ce by La leads to a slight decrease of the transition temperature in the explored range together with a significant reduction of the magnetocaloric magnitudes: about ‒1.0 J/(kg∙K) and about ‒0.2 K per atom fraction of La for the isothermal entropy and adiabatic temperature changes for 5 T, respectively. Graphical abstract: Ce(La)In 2 series undergoes a low-hysteretic fist-order magnetic transition near 20 K, with a significant magnetocaloric performance together with moderate materials criticality.