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

ABSTRACT 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.