Engineering the Magnetocaloric Effect in NdT₄B (T=Fe, Co, Ni)

Magnetic refrigeration is a more efficient and environmentally friendly alternative to conventional gas-cycle cooling. The main challenge in this field is finding materials with a large enough magnetocaloric effect (MCE) that peak near room temperature. In ferromagnets, the MCE peaks near the Curie temperature so it is helpful to find materials that order near room temperature. Here we present our results on NdT₄B (T=Fe, Co, Ni) where the Curie temperature and MCE can be tuned by varying the ratio of transition metals. We construct three triangle plots, showing the Curie temperature, maximum entropy change, and refrigerant capacity for various compositions of NdT4B compounds. From these plots we predict the optimal composition that maximizes the MCE at room temperature.