Magnetocaloric effect for the topological semimetal CoSnS due to the antiferromagnetic coupling of the bulk and surface spin-polarized phases
arXiv:2410.05138 · doi:10.1016/j.jmmm.2025.172998
Abstract
We experimentally investigate magnetocaloric effect for the topological magnetic Weyl semimetal CoSnS in a wide temperature range. The isothermal magnetic entropy change is calculated from the experimental magnetization curves by using Maxwell relation. In addition to the expected peak at the Curie temperature , we obtain another one at the temperature of the hysteresis inversion, which is the main experimental result. The inverted hysteresis usually originates from the antiferromagnetic coupling between two magnetic phases. For CoSnS topological magnetic Weyl semimetal these phases are the ferromagnetic bulk and the spin-polarized topological surface states. Thus, the pronounced magnetocaloric effect at is determined by the bulk magnetization switching by the exchange bias field of the surface spin-polarizad phase, in contrast to the ferromagnetic-paramagnetic transition at the Curie temperature . For possible applications of magnetocaloric effect, Weyl semimetals open a new way to shift from ferromagnetic to the antiferromagnetic systems without loss of efficiency, but with higher reversibility and with smaller energy costs.