Manipulation of\nExchange Bias in Two-Dimensional van\nder Waals Ferromagnet Near Room Temperature

As a host for exchange bias (EB), van der Waals (vdW)\nmagnetic\nmaterials have exhibited intriguing and distinct functionalities from\nconventional magnetic materials. The EB in most vdW systems is far\nbelow room temperature, which poses a challenge for practical applications.\nHere, by using Kerr microscopy, we demonstrate a record-high blocking\ntemperature that approaches room temperature and a huge positive EB\nfield that nears 2 kOe at 100 K in naturally oxidized two-dimensional\n(2D) vdW ferromagnetic Fe<sub>3</sub>GaTe<sub>2</sub> nanoflakes.\nMoreover, we realized a reversible manipulation of both the presence/absence\nand positive/negative signs of EB via a training magnetic field without\nmultiple field cooling processes. Thus, our study clearly reveals\nthe robust, sizable, and sign-tunable EB in vdW magnetic materials\nup to near room temperature, thereby establishing Fe<sub>3</sub>GaTe<sub>2</sub> as an emerging room-temperature-operating vdW material and\npaving the way for designing practical 2D spintronic devices.