Strained van der Waals Metallic Magnet for Photomagnetic Modulation and Spin Photodiode Application

All-optical magnetization reversal provides a low-power approach for investigating spin state manipulation in 2D magnets. However, the ambient observation of photomagnetic coupling presents significant challenges due to the low Curie temperatures exhibited by most 2D magnets. Herein, a mixed-dimensional heterostructure comprising a surface-oxidized Fe3GeTe2 nanosheet with enhanced magnetic properties and individual semiconducting ZnO nanorod is proposed to explore proximity photomagnetic modulation and spin-enhanced photodetection behaviors. The surface curvature of ZnO nanorod induces pronounced strains for Fe3GeTe2 nanosheet, leading to its anomalous Raman polarization and spin ordering at room temperature. Strain-activated itinerant spin electrons are immobilized on the O-2p orbitals of adjacent ZnO, thereby facilitating the optical demagnetization process in Fe3GeTe2 without aid of magnetic field. First-principles calculations together with in situ characterization experiments further confirm that the primary charge transfer channel involves coupling between Fe3+ and oxygen vacancy defects anchored at heterointerfaces. The rapid establishment of magnetization by illumination in ZnO nanorod contributes to spin-tunneling-enhanced photocurrent, device response dynamics, polarization detection and ultraviolet imaging capability. These findings offer valuable insights to optimize the optoelectronic properties of conventional semiconductors and advance complex dimensional spin-optoelectronic devices. Mixed-dimensional magnetic van der Waals heterostructure is established to induce room temperature 2D ferromagnetism and corresponding photomagnetic effect. The spin-related charge transfer between Fe species and oxygen vacancy defects localized at the heterointerface is facilitated by illumination and contributes to spin-tunneling-enhanced photoconductivity performance. These findings offer valuable insights to manipulate photomagnetic process and optimize the optoelectronic properties of conventional semiconductors. image