New coercivities and Curie temperatures emerged in van der Waals homostructures of Fe3GeTe2

Abstract

Stacking of two-dimensional van der Waals (vdW) materials has emerged as a vital approach for investigating the complex interplay between coexisting materials, leading to novel electronic, photonic, and spintronic phenomena such as strong electronic correlation, enhanced Zeeman splitting of excitons, and the magnetic proximity effect. While most of the previous focus was on the electronic and photonic properties of vdW hetero-/homostructures, the study of magnetism in hetero-/homostructures remains lacking, though phenomena such as layer-dependent magnetism already highlighted the critical role of interlayer coupling in magnetism of layered systems. Here, we report an interesting two-step magnetic hysteresis loop in the homostructure of the layered vdW magnet ${\mathrm{Fe}}_{3}{\mathrm{GeTe}}_{2}$ (FGT). The two coercivities in the homostructure differ from that of each constituent FGT layer, indicating that the two constituents interact mutually but do not merge into a thicker uniform material. The Curie temperature (${T}_{\mathrm{C}}$) of the homostructure is in between that of the thinner and thicker constituents, further implying that the two constituent layers interact yet without forming a naturally occurring thicker layer. Our results highlight the unexplored opportunities that the rich interplay within vdW magnet homostructures can be employed to create emerging magnetic properties and develop novel multistate devices.