Anisotropic magnetic entropy change in Cr2X2Te6(X=Siand Ge)

Intrinsic, two-dimensional (2D) ferromagnetic semiconductors are an important class of materials for spintronics applications. ${\mathrm{Cr}}_{2}{X}_{2}{\mathrm{Te}}_{6}\phantom{\rule{4pt}{0ex}}(X=\text{Si}\phantom{\rule{4pt}{0ex}}\text{and Ge})$ semiconductors show 2D Ising-like ferromagnetism, which is preserved in few-layer devices. The maximum magnetic entropy change associated with the critical properties around the ferromagnetic transition for ${\mathrm{Cr}}_{2}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}\ensuremath{-}\mathrm{\ensuremath{\Delta}}{S}_{M}^{\text{max}}\ensuremath{\sim}5.05$ J ${\mathrm{kg}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ is much larger than $\ensuremath{-}\mathrm{\ensuremath{\Delta}}{S}_{M}^{\text{max}}\ensuremath{\sim}2.64$ J ${\mathrm{kg}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ for ${\mathrm{Cr}}_{2}{\mathrm{Ge}}_{2}{\mathrm{Te}}_{6}$ with an out-of-plane field change of 5 T. The rescaled $\ensuremath{-}\mathrm{\ensuremath{\Delta}}{S}_{M}(T,H)$ curves collapse onto a universal curve independent of temperature and field for both materials. This indicates similar critical behavior and 2D Ising magnetism, confirming the magnetocrystalline anisotropy that could preserve the long-range ferromagnetism in a few layers of ${\mathrm{Cr}}_{2}{X}_{2}{\mathrm{Te}}_{6}$.