Self‐Intercalated CrxSy: 2D Ferrimagnetic Materials From Low‐Temperature to Room‐Temperature

The advancement of spintronics relies on the development of 2D magnetic materials with robust room‐temperature properties. However, challenges such as low Curie temperatures (T C ) and ambient instability have hindered their practical applications. In this study, we employ chemical vapor deposition (CVD) combined with salt‐assisted methods and optimize growth parameters to synthesize phase‐tunable Cr x S y compounds, including rhombohedral Cr 2 S 3 (ferrimagnetic below 120 K), trigonal Cr 5 S 6 (room‐temperature ferrimagnetic), and hexagonal CrS (antiferromagnetic). Our findings reveal that self‐intercalation of Cr atoms significantly modifies the lattice structure, electronic states, and magnetic properties of these materials. Cr 5 S 6 exhibits half‐metallic characteristics with room‐temperature ferrimagnetism, representing a significant advancement for practical 2D magnetic materials. The charge transfer from self‐intercalated Cr atoms and superexchange interactions mediated by sulfur p ‐orbitals are identified as key mechanisms driving these tunable properties. This work highlights self‐intercalation as a transformative strategy for engineering high‐performance 2D magnetic materials, providing insights for advancing next‐generation spintronic devices.