Engineering the magnetocaloric effect in Nd <i>T</i> 4B

Abstract

We present a comprehensive study of the magnetocaloric effect (MCE) in the NdT4B system, where T = Fe, Co, and Ni. These compounds are ferromagnetic kagome materials with tunable ordering temperatures, transition width, and magnetic moments depending on the choice of transition metals. Thus, they are good candidates for investigating the MCE. We characterize the MCE using standard metrics and construct ternary phase diagrams as functions of Fe, Co, and Ni concentrations. Using these phase diagrams, we engineer the composition NdFe1.15Co0.46Ni2.39B to maximize the MCE. Interestingly, the NdT4B system shows a notable entropy change over a wide temperature range (∼10–650 K), and particular compositions have MCEs spanning hundreds of Kelvin, making this a suitable system to study for technologies used in a wide range of temperatures. In a few cases, we observe a two-peak MCE. These two transitions, releasing comparable entropy, provide an interesting platform to study for applications in multi-stage cooling.