Intrinsic Ferromagnetism in 2D Cr_xSe_1-x Crystals

In the last two years, several two-dimensional (2D) materials of magnetic order, including CrI₃ and Cr₂Ge₂Te₆, have been observed, which represents a breakthrough in the field of 2D magnetism and opens up opportunities for device applications integrating these magnets with other van der Waals (vdW) crystals. However, most of these materials are vdW structures which rely on the mechanical exfoliation technique to obtain ultra-thin flakes. Furthermore, most 2D magnets have poor stability and low magnetic transition temperature, which limit their practical application. To search for 2D materials with improved magnetic properties, one needs to look beyond vdW crystals. In this work, a 2D non-vdW magnetic material, Cr_xSe_1-x, has been synthesized using an ambient pressure chemical vapor deposition method. The magnetic characterization demonstrated that the thin flakes exhibit ferromagnetic properties with ordering temperature above 250 K. These results may pave the way for practical applications of 2D magnets.