Large anisotropic magnetocaloric effect in ferromagnetic semimetal PrAlSi

Abstract

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 −ΔSM=22.6J/kgK near the Curie temperature TC=17.8K under a magnetic field change of μ0ΔH=5T along the magnetic easy c axis. A highly relevant feature is the small crystalline electric field splitting of the Pr3+ (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 Pr3+ 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 TC are features further enhancing the magnetocaloric effect. Given the strong magnetic anisotropy, a large rotating magnetocaloric effect becomes achievable in this material.