Influence of domain wall anisotropy on the current-induced hysteresis loop shift for quantification of the Dzyaloshinskii-Moriya interaction

Using several material systems with various magnitudes of the interfacial Dzyaloshinskii-Moriya interaction (DMI), we elucidate a critical influence of domain wall (DW) anisotropy on the current-induced hysteresis loop shift scheme widely employed to determine the magnitude of the Dzyaloshinskii-Moriya effective field (HDMI). Taking into account the DW anisotropy in the analysis of the hysteresis loop shift, which has not been included in the original model [Phys. Rev. B 93, 144409 (2016)10.1103/PhysRevB.93.144409], we show that it provides quantitative agreement of HDMI with that determined from an asymmetric bubble expansion technique for small DMI material systems. For large DMI systems, the DW anisotropy gives rise to nonlinearity in the response of spin-orbit torque efficiency to the in-plane magnetic field, from which HDMI can be determined. The consequence of the directions of DW motion in the Hall device on the current-induced shift of the hysteresis loop is also discussed. The present findings deliver important insights for reliable evaluation of DMI, which are of significance in spintronics with chiral objects.