Rotating magnetocaloric effect in the ferromagnetic Weyl semi-metal Co${}_3$Sn${}_2$S${}_2$

Abstract

The rotating magnetocaloric effect (RMCE) is a recent interest in magnetic refrigeration technique in which the cooling effect is attained by rotating the anisotropic magnetocaloric material from one orientation to the other in a fixed magnetic field. In this work, we report the anisotropic magnetocaloric properties of single crystals of the ferromagnetic Weyl semimetal Co${}_3$Sn${}_2$S${}_2$ for magnetic field $H\parallel c$ axis and $H\parallel ab$ plane. We observed a significant (factor of $2$) difference between the magnetocaloric effect measured in both orientations. The rotating magnetocaloric effect has been extracted by taking the difference of the magnetic entropy change ($\Delta S_M$) for fields applied in the two crystallographic orientations. In a scaling analysis of $\Delta S_M$, the rescaled $\Delta S_M(T,H)$ vs reduced temperature $\theta$ curves collapse onto a single universal curve, indicating that the transition from paramagnetic to ferromagnetic phase at 174~K is a second order transition. Furthermore, using the power law dependence of $\Delta S_M$ and relative cooling power RCP, the critical exponents $\beta$ and $\gamma$ are calculated, which are consistent with the recent critical behavior study on this compound \cite{Yan2018}.

5 pages, 5 figures