Room temperature ferromagnetism in ultra-thin van der Waals crystals of 1T-CrTe₂

Although many emerging new phenomena have been unraveled in two dimensional (2D) materials with long-range spin orderings, the usually low critical temperature in van der Waals (vdW) magnetic material has thus far hindered the related practical applications. Here, we show that ferromagnetism can hold above 300 K in a metallic phase of 1T-CrTe₂ down to the ultra-thin limit. It thus makes CrTe₂ so far the only known exfoliated ultra-thin vdW magnets with intrinsic long-range magnetic ordering above room temperature. An in-plane room-temperature negative anisotropic magnetoresistance (AMR) was obtained in ultra-thin CrTe₂ devices, with a sign change in the AMR at lower temperature, with -0.6% and +5% at 300 and 10 K, respectively. Our findings provide insights into magnetism in ultra-thin CrTe₂, expanding the vdW crystals toolbox for future room-temperature spintronic applications.