Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching a...Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2022YFA1204000)partly by the National Natural Science Foundation of China (Grant Nos.12274405,12304155,and 12393831)the Beijing Natural Science Foundation (Grant No.Z230006)。
文摘Accurate quantification of the spin–orbit torques(SOTs) is critical for the identification and applications of new spin-orbitronic effects. One of the most popular techniques to quantify the SOTs is the “switching angle shift”, where the applied direct current is assumed to shift, via domain wall depinning during anti-domain expansion, the switching angle of a perpendicular magnetization in a linear proportional manner under a large rotating magnetic field. Here, we report that, for the most commonly employed perpendicular magnetization heterostructures in spintronics(e.g., those based on FeCoB, Co, and Co/Ni multilayers), the switching angle shift considerably misestimates the SOT within the domain wall depinning analysis of the slope of linear-in-current scaling and may also have a non-zero residual value at zero direct current. Our experiments and simulations unveil that the switching angle shift is most likely dominated by chiral asymmetric nucleation rather than expansion of anti-domains. The in-plane field from external magnets and current-induced SOTs lowers the perpendicular nucleation field and thus reduces the required switching angle, ultimately leading to an underestimation of SOTs by domain wall depinning analysis. These results have advanced our understanding of magnetization switching in spintronic devices.
