Degradation of the Magnetocaloric Effect in Fe₄₈Rh₅₂ Alloys under Cyclic Magnetic Field

The direct measurements of the adiabatic temperature change under cyclic conditions have been carried out for Fe₄₈Rh₅₂ alloys obtained by different heat treatment protocols. Furthermore, the magnetocaloric long-term performance has been estimated. The results demonstrate that the degradation of the magnetocaloric properties observed in FeRh can depend on the microstructure of the alloys. Besides, the selection of the cycling temperature can affect the performance as well. The magnetic measurements carried out after the cyclic experiment revealed a shift of the transition towards lower temperatures, which can be correlated to the possible stress that was accumulated during the repetitive magnetostructural transition. Then, it has been shown that the degraded material can be healed by a low temperature annealing those results in the recovery of the magnetostructural transition. The outcome can give a hint for the efficient design of magnetocaloric alloys and the selection of the working temperature in order to diminish the degradation effects.