Multicaloric effects and magnetostructural coupling in the Cr2Ge2Te6 van der Waals crystal

Abstract

Materials with significant coupling between magnetism and their crystal structure are prone to exhibit multicaloric effects, which offer a novel approach to addressing the bottlenecks of ecologic solid-state refrigeration by optimizing the interplay of multiple driving fields. Here we uncover the multicaloric properties of CrGeTe, establishing ferromagnetic van der Waals (vdW) crystals, famous for their spintronics applications, as a previously unrecognized class of multicaloric materials. By combining magnetization measurements with an ab initio disordered local moment theory, we report, for the first time, pronounced barocaloric and multicaloric effects induced by the application of magnetic fields and hydrostatic pressure around CrGeTe’s ferromagnetic phase transition. Our experimental and ab initio analysis quantifies the underlying magnetostructural coupling in this material, which accounts for approximately 25% of the total multicaloric entropy change. Significant multicaloric effects are expected to be found in other vdW ferromagnets with strong magnetostructural coupling.