Theoretical study on magnetocaloric effect and its electric-field regulation in CrI₃/metal heterostructure

The extraordinary properties of a heterostructure by stacking atom-thick van der Waals (vdW) magnets have been extensively studied. However, the magnetocaloric effect (MCE) of heterostructures that are based on monolayer magnets remains to be explored. Herein, we deliberate MCE of vdW heterostructure composed of a monolayer CrI₃ and metal atomic layers (Ag, Hf, Au, and Pb). It is revealed that heterostructure engineering by introducing metal substrate can improve MCE of CrI₃, particularly boosting relative cooling power to 471.72 µJ m⁻² and adiabatic temperature change to 2.1 K at 5 T for CrI₃/Hf. This improved MCE is ascribed to the enhancement of magnetic moment and intralayer exchange coupling in CrI₃ due to the CrI₃/metal heterointerface induced charge transfer. Electric field is further found to tune MCE of CrI₃ in heterostructures and could shift the peak temperature by around 10 K in CrI₃/Hf, thus manipulating the working temperature window of MCE. These theoretical results could enrich the research on low-dimensional magnetocaloric materials.