High magnetic anisotropy and magnetocaloric effects in single crystal Cr${}_2$Te${}_3$

Abstract

We report a systematic investigation of anisotropic magnetocaloric effects in single crystal Cr${}_2$Te${}_3$. Single crystal samples are synthesized by chemical vapor transport and characterized by x-ray and Laue diffraction methods. The maximum magnetic entropy change $-\Delta S_{\text{M}}^{\text{max}}$ is 4.50 J kg${}^{-1}$ K${}^{-1}$ for the easy c-axis (3.36 J kg${}^{-1}$ K${}^{-1}$ for the hard ab-plane) and the relative cooling power RCP is 296.7 J kg${}^{-1}$ for the easy c-axis (183.84 J kg${}^{-1}$ for the hard axis ab-plane) near the Curie temperature for a magnetic field change of 9 T. The magneto-crystalline anisotropy constant K${}_u$ is estimated to be 486.92 kJ m${}^{-3}$ at 146 K, decreasing to 148.60 kJ m${}^{-3}$ at 168 K. Meanwhile, the maximum of the rotational magnetic entropy change $\Delta S_{\text{M}}^{\text{R}}(T,H)$ between the c-axis and the ab-plane is about 1.14 J kg${}^{-1}$K${}^{-1}$ for magnetic-field change of 9 T. The critical exponents are estimated by analyzing magnetocaloric effects, which indicate 2D-Ising type magnetic system. The accuracy of estimated critical exponents is verified by scaling analysis. The maximum magnetic entropy change $-\Delta S_{\text{M}}^{\text{max}}$ $\approx$5.25 J kg${}^{-1}$ K${}^{-1}$ (along the c-axis) and the corresponding adiabatic temperature change $\Delta T_{\text{ad}}$ $\approx$3.31 K (along the c-axis) are estimated by analyzing heat capacity measurements with a magnetic field up to 9 Tesla.