Field-Free switching of Antiferromagnetically Coupled Co/Pd-Based perpendicular multi-layer via combined spin torques

• Fabrication of GMR pillar devices with Co/Pd-based perpendicular magnetized SAF free layer. • For the first time, field-free SOT switching was observed under the STT assistance in SAF free layers. • STT assistance in SAF is lower than ferromagnetic layer, due to competing of opposed magnetization components. Spin-transfer torque combined with spin–orbit torque switching is considered a highly promising writing mechanism for advancing large storage density magnetic random-access memory with perpendicular magnetic anisotropy, due to its capability for field-free operation. Meantime, synthetic antiferromagnet has also gathered significant attention owing to its advantage in enhancing thermal stability while keeping the switching current low, which is crucial for achieving high-capacity MRAM. We manufactured Giant Magnetoresistance (GMR) devices utilizing a synthetic antiferromagnetic (SAF) free layer, and found that the SOT switching was assisted by STT even in SAF free layer, which has not been reported, and that the effect of STT assisting was significantly different from that for ferromagnetic free layer.