Artificial Room-Temperature Ferromagnetism of Bulk van der Waals VSe.

Originating from spin and orbital motion, van der Waals (vdW) ferromagnetism has emerged as a significant platform to experimentally access the fundamental physics of magnetism in reduced dimensions, including quantum computing, sensing, and data storage. However, currently, available vdW ferromagnetic materials can be achieved with mechanical exfoliation and low-temperature operation, which completely limits the monolithic integration of vdW ferromagnets with other functional materials. Nonetheless, the direct synthesis of room-temperature vdW ferromagnets has not been achieved commercially, owing to the imprecise control of the layer-by-layer growth, high-temperature synthesis, and low yield. To overcome these limitations, herein, an artificial vdW ferromagnetic platform has been reported, which activates the nano-crystallization and its corresponding ferromagnetism in bulk VSe via Ar + HS plasma sulfurization. Sweeping the magnetic field, vdW ferromagnetism has been spatially resolved, which experimentally correlates with magnetization reversal behavior and domain pinning effects. Furthermore, nano-crystallization of VSe is clearly validated with transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and selected area diffraction analysis. In conclusion, it is envisioned that the artificial vdW ferromagnetic platform can artificially inject the ferromagnetism in bulk vdW VSe, which has not been possible previously.