Magnetic contrast scanning transmission x-ray microscopy imaging on an MBE-grown Bi2Te3/Fe3GeTe2 heterostructure: insights from micromagnetic simulations

The field of spintronics seeks to harness electron spins for data storage and processing, offering increased efficiency by exploiting the spin degree of freedom. Two-dimensional van der Waals magnets, with their atomically thin interfaces and customizable proximity effects, show great potential for such applications. Among them, the Bi2Te3/Fe3GeTe2 heterostructure, grown via molecular-beam epitaxy (MBE) at wafer-scale, is particularly notable due to its strong spin-orbit coupling and topologically non-trivial band structure [1]. Using magnetic contrast scanning transmission X-ray microscopy at the MAXYMUS beamline of the BESSY II synchrotron, we identified highly fractured magnetic domain structure in MBE-grown Bi2Te3/Fe3GeTe2 thin films— a type of skyrmion-like domain previously unreported in exfoliated Fe3GeTe2. In this talk, we will explore the complex interplay between the interfacial Dzyaloshinskii–Moriya interaction arising from the proximity coupling in Bi2Te3/Fe3GeTe2 and the highly fractured magnetic domains observed in Fe3GeTe2. With insights drawn from micromagnetic simulations using MuMax³ [2], we will also discuss the competing long-range and short-range magnetic orders in epitaxial Bi2Te3/Fe3GeTe2 as influenced by varying temperatures, field cooling histories, and layer thicknesses.