Dissipative solitons signature in achiral Néel magnetic domain walls driven by spin-orbit torque

Abstract

[EN]The dynamics of achiral Néel domain walls (DWs) driven by spin-orbit torque in wide ferromagnetic strips is investigated. The study reveals that these DWs cease motion above a certain threshold current density, while their internal magnetic moments exhibit a spatial modulation characterized by a 180∘ rotation leading to a quasi-sinusoidal distortion of their shape. Unlike achiral DWs in narrow strips, which stop because they take on a Bloch configuration, achiral DWs in wide strips stop due to the internal diffusive torques originating from exchange interaction that counterbalance locally the torques contributing to the DW dynamics. If these torques are perfectly balanced, the DW remains stationary, whereas the slighter imbalance triggers complex nonlinear dynamics, including continuous oscillation of the domain wall magnetization or quasi-periodic explosions in which the domain wall “cracks" and recovers its structure afterwards. Our findings unveil a dissipative solitonic signature in achiral domain walls driven by SOT, akin to dissipative solitons observed in other scientific fields. This work paves the way for exploring nonlinear spatio-temporal dynamics in DWs with potential applications in logic and neuromorphic computing.