Domain wall propagation by spin-orbit torques in in-plane magnetized systems

Abstract

The effect of damping-like spin-orbit torque (DL SOT) on magnetic domain walls (DWs) in in-plane magnetised soft tracks is studied analytically and with micromagnetic simulations. We find that DL SOT drives vortex DWs, whereas transverse DWs, the other typical DW structure in soft tracks, propagate only if the Dzyaloshinskii-Moriya interaction (DMI) is present. The SOT drive can add to, and be more efficient than, spin-transfer torque (STT), and so may greatly benefit applications that require in-plane DWs. Our analysis based on the Thiele equation shows that the driving force arises from a cycloidal distortion of the DW structure caused by geometrical confinement or DMI. This distortion is higher, and the SOT more efficient, in narrower, thinner tracks. These results show that the effects of SOT cannot be understood by simply considering the effective field at the center of the structure, an ill-founded but often-used estimation. We also show that the relative magnitude of STT and DL SOT can be determined by comparing the motion of different vortex DW structures in the same track.

arXiv commentAccepted for publication in Physical Review B Rapid Communications

References in corpus (10)

• The design and verification of Mumax3
• Current-driven dynamics of chiral ferromagnetic domain walls
• Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films
• Matching domain wall configuration and spin-orbit torques for very efficient domain-wall motion
• Interfacial Dzyaloshinskii-Moriya interaction in Pt/CoFeB films: effect of the heavy-metal thickness
• Domain structure in CoFeB thin films with perpendicular magnetic anisotropy
• Current-driven vortex domain wall dynamics by micromagnetic simulations
• Magnetic domain walls displacement : automotion vs. spin-transfer torque
• Exchange stiffness in ultrathin perpendicularly-magnetized CoFeB layers determined using spin wave spectroscopy
• Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks