Ultralow Current Switching of Synthetic‐Antiferromagnetic Magnetic Tunnel Junctions Via Electric‐Field Assisted by Spin–Orbit Torque

Spintronic devices, especially electric‐field and spin–orbit torque driven magnetic tunnel junctions (MTJs), are promising candidates to replace the current memory and logic components for satisfying future computing demands. Current spin–orbit torque based MTJ devices with a single free layer and spin Hall channel still face high current density for switching. Here, 150‐nm perpendicular MTJs are designed and fabricated with a synthetic‐antiferromagnetic free layer and a bilayered spin Hall channel. The switching behavior is investigated via combination of forces from electric‐field and spin–orbit torque, where the electric field can modulate the exchange coupling of the synthetic‐antiferromagnetic free layer. Through an assistance of spin–orbit torque, bidirectional switching is obtained with switching current density as low as 3 × 103 A cm−2, which is two orders of magnitude lower than that of the current best reported values. These results suggest that electric‐field switching of synthetic‐antiferromagnetic MTJs could be a promising approach for reducing write current density of spintronic devices. This work presents an important advance in perpendicular magnetic tunnel junctions (p‐MTJs) with synthetic‐antiferromagnetic free layers and bilayered spin Hall channels switched through voltage‐controlled exchange coupling and spin–orbit torque. 150‐nm p‐MTJs show bidirectional switching behavior with the switching current density JVCEC ≈ 3 × 103 A cm−2 and JSOT ≈ 7 × 107 A cm−2, suggesting electric‐field switching of synthetic‐antiferromagnetic p‐MTJs is a promising approach for ultralow power spintronic devices.