L-Shaped Electrode Design For High-Density Spin-Orbit Torque Magnetic Random Access Memory With Perpendicular Shape Anisotropy

Magnetic tunneling junctions with strong perpendicular shape anisotropy attract attention due to their high-density magnetic random access memory. As thermal stability increases, the power consumption also increases. To solve this problem, devices are made to be driven by spin-orbit torque (SOT) instead of spin-transfer torque. However, the assisting field needed for deterministic switching is a major obstacle for SOT devices. In this work, we demonstrate an L-shaped electrode structure attached to the magnetic recording layer to induce a composite SOT, achieving high-speed and field-free magnetization switching. Meanwhile, a comparative study between L-shaped and sidewall electrode structure demonstrates that the L-shaped structure leads to fast and low-power switching. Finally, the switching characteristic at various current densities and spin Hall angles is studied and it turns out that to achieve high-speed reversal, the current density and the spin Hall angle need to be optimized, which might be attributed to strong in-plane effective field component disturbance. The novel L-shaped structure is feasible for high-speed, low-power and deterministic switching and has great potential in spintronic applications.