All two-dimensional van der Waals magnetic tunneling junctions

Magnetic tunnel junctions (MTJs) have exhibited significant application potential in magnetic sensors, magnetic random-access memory, spin-based logic gates, etc. However, conventional MTJ devices consisting of magnetic thin films usually suffer from interface defects and low scaling, severely compromising device performance. In contrast, all two-dimensional (2D) van der Waals (vdW) MTJs offer an effective solution to avoid these problems, due to their atomically flat surfaces, suppressed interfacial mixing, and low dimensionality. In this review, we provide a systematic overview of recent advancements in all-2D vdW MTJs involving both spin-valve and spin-filter configurations. The discussed systems are classified according to the types of 2D magnetic materials. Then, the effective strategies for modulating the performance of MTJs are introduced, such as regulating the bias voltage/current, the thickness of the tunneling layer, and spin angles. Finally, the challenges and prospects for the future development of all-2D MTJs are discussed, highlighting the potential for realizing breakthroughs in this field.