Subnanosecond Field-Free Switching of a Wafer-Scalable van der Waals Ferromagnet at Room Temperature.

Electrical manipulation of magnetism in 2D van der Waals (vdW) ferromagnet (FM) holds promise for next-generation spintronic devices. Investigating field-free, ultrafast switching at room temperature in wafer-scalable vdW heterostructures can advance the development of faster memories and enhance the understanding of magnetization switching mechanisms in 2D FMs. In this study, field-free, room temperature spin-orbit torque (SOT) switching at subnanosecond timescales in a wafer-scalable Fe3GaTe2/Pt heterostructure by epitaxial growth engineering is demonstrated. The introduction of a variable concentration gradient of Fe is used to establish the coexistence of in-plane magnetic anisotropy (IMA) and perpendicular magnetic anisotropy (PMA) within the ferromagnetic layer. The field-free switching, driven by the SOT from Pt, is achieved by using the IMA component to break the in-plane symmetry during the switching process. This work paves the way for the integration of efficient 2D vdW materials in advanced spintronic devices and faster memory technologies.