  Magnetic tunnel junctions (MTJs) based on all-two dimensional (2D) van der
Waals heterostructures with sharp and clean interfaces in atomic scale are
essential for the application of next-generation spintronics. However, the lack
of room-temperature intrinsic ferromagnetic crystals with perpendicular
magnetic anisotropy has greatly hindered the development of vertical MTJs. The
discovery of room-temperature intrinsic ferromagnetic 2D crystal Fe3GaTe2 has
solved the problem and greatly facilitated the realization of practical
spintronic devices. Here, we demonstrate a room-temperature MTJ based on
Fe3GaTe2/WS2/Fe3GaTe2 heterostructure. The tunnelling magnetoresistance (TMR)
ratio is up to 213% with high spin polarization of 72% at 10 K, the highest
ever reported in Fe3GaTe2-based MTJs up to now. The tunnelling spin-valve
signal robustly exists at room temperature (300 K) with bias current down to 10
nA. Moreover, the spin polarization can be modulated by bias current and the
TMR shows a sign reversal at large bias current. Our work sheds light on the
potential application for low-energy consumption all-2D vdW spintronics and
offers alternative routes for the electronic control of spintronic devices.
