Strain-Induced Interlayer Magnetic Coupling Spike of the Two-Dimensional van der Waals Material Fe5GeTe2

A stronger interlayer magnetic coupling (ILMC) can open up new opportunities in spintronic devices. Numerous publications have demonstrated that ILMC is continuously evolving, even in the context of magnetic phase change. Here, we observe an extraordinary discontinuous transition (ILMC spike) in a two-dimensional (2D) van der Waals (vdW) material, Fe5GeTe2 (F5GT). The ILMC spikes from 1.15 to 12.79 meV/f.u when a 3% in-plane biaxial strain is applied. Additionally, the applied in-plane strain significantly enhances the magnetic anisotropy energy (MAE) of the system, triggering a sharp transition between the in-/off-plane configurations in multilayer F5GT.