Large table-like magnetocaloric effect in boron-doped Er₅Si₃B_0.5 compound

In this work, Er₅Si₃B_0.5 compound with the Mn₅Si₃-type hexagonal structure was synthesized, and the structure, magnetic properties, and the magnetocaloric effect were investigated theoretically and experimentally. The magnetic measurement results show a complex successive magnetic transition below T N . However, the magnetization of the Er₅Si₃B_0.5 compound below T N is saturated under lower magnetic field relative to the Er₅Si₃ compound. Theoretical calculation indicates that this was attributed to the enhanced inter-orbital exchange interaction after doping B element. The complicated successive magnetic transitions contribute to the table-like magnetocaloric effect observed in the Er₅Si₃B_0.5 compound with a wide temperature region. The maximum magnetic entropy change and the temperature averaged entropy change (30) are 10.1 and 9.02 J/kg K for the Er₅Si₃B_0.5 compound under varying magnetic fields from 0 to 5 T, respectively. The temperature averaged entropy change (30) is reduced by just 11% compared to the maximum magnetic entropy change. While presenting an ideal magnetic refrigeration material with a large table-like magnetocaloric effect for hydrogen liquefaction, our work also demonstrates the feasibility of regulating magnetic behavior through enhanced orbital exchange interactions to develop magnetic refrigeration materials with outstanding performance.