Large anisotropic magnetocaloric effect in ferromagnetic semimetal PrAlSi

We report on the large anisotropic magnetocaloric effect of PrAlSi, a ferromagnetic semimetal of current interest with a probable topologically nontrivial electronic structure. The maximum magnetic entropy change amounts to - Δ _{S M} = 22.6 J / kg K near the Curie temperature _{T C} = 17.8 K under a magnetic field change of _{μ 0} Δ H = 5 T along the magnetic easy c axis. A highly relevant feature is the small crystalline electric field splitting of the ^{Pr 3 +} ( J = 4 ) multiplet, which appears to be comparable with the effective exchange interaction in the magnetic ordering. This leads to the full saturation moment of the ^{Pr 3 +} ion in small fields and an accumulation of magnetic entropy in the vicinity of the magnetic ordering. The weakly first-order nature of the ferromagnetic transition and the subsequent reentrant spin-glass transitions below _{T C} are features further enhancing the magnetocaloric effect. Given the strong magnetic anisotropy, a large rotating magnetocaloric effect becomes achievable in this material.