Twist-angle dependent all van der Waals spin-valve operations

Two-dimensional (2D) magnetic materials and their heterostructures with atomically clean van der Waals (vdW) interfaces provide an excellent experimental platform to realize novel spintronic device operations. In addition, twistronics, whose primary device attribute is associated with the alignment angles of the single-crystalline layered materials, has been an active research field for the past several years. However, experimental realizations of twistronics employing the versatility of twist angles with 2D magnetic materials have not been demonstrated yet. Here we present the twist-angle dependent spin-valve operations with all vdW-assembled vertical magnetic tunnel junctions (MTJs) made of 2D metallic ferromagnet Fe₃GeTe₂ (FGT) and tunnel insulator hexagonal boron nitride (hBN). We have found that vertical spin-dependent charge transport behaviors of the all-vdW-assembled vertical MTJs are highly sensitive to the twist angles of the 2D metallic ferromagnets and the relative spin configurations of the FGT electrodes. The tunneling magnetoresistance ratio of the FGT-hBN-FGT spin valves is measured to be as high as ~ 480% for the device with a 2° twist angle and continually decreases to ~ 100% and lower as the misalignment angle increases. These unprecedented twist-angle dependent spin-valve operations provide a new control knob for low-dimensional spintronic applications.