Tailoring CoFeB/MgO-Interface for Enhanced Perpendicular Magnetic Anisotropy and Voltage-assisted SOT switching

This talk focuses on engineering the CoFeB/MgO interface to enhance perpendicular magnetic anisotropy (PMA) and voltage-controlled magnetic anisotropy (VCMA) for efficient spin-orbit torque (SOT) switching in spintronic devices. The Ta/CoFeB/MgO heterostructure is a promising platform for next-generation memory technologies due to its strong interfacial anisotropy and compatibility with CMOS processes. However, its SOT switching efficiency remains limited. This talk presents a strategy to tailor interfacial properties by incorporating ultrathin Mg and Ir insertion layers, which significantly boost the Rashba-type interfacial spin-orbit fields. These insertions not only enhance PMA and VCMA coefficients but also reduce the critical current for SOT switching, enabling more energy-efficient device operation [1,2].

The role of Rashba-Edelstein effect at the engineered interfaces is discussed, supported by harmonic Hall and Anomalous Hall characterizations. The combined influence of chemical modification and interfacial symmetry breaking demonstrates a path toward low-power, voltage-assisted magnetization switching.   References:
[1] Fukami et al., Nat. Mater., 15, 535–541 (2016).
[2] Liu et al., Phys. Rev. Lett., 109, 096602 (2012).