Impact of Nonlinear Viscous Damping on Strain-Mediated Domain Wall Propagation in Hexagonal Magnetostrictive Materials

Magnetic domain walls are promising information carriers for developing next-generation high-processing speed spintronic devices. While extensive research has been conducted on field- and current-driven domain wall propagation from fundamental theoretical and practical applications viewpoint, the strain-controlled manipulation of domain walls in magnetostrictive materials with different crystal structures has recently gained significant attention. In this work, we theoretically investigate strain-driven domain wall motion in a transversely isotropic hexagonal magnetostrictive layer, incorporating the influence of nonlinear viscous damping. Our analysis is based on the one-dimensional extended Landau–Lifshitz–Gilbert equation, which captures the combined effects of a tunable magnetic field, spin-polarized current, magnetoelastic and anisotropy fields, and crystal symmetry. By applying the traveling wave method, we derive expressions for key dynamics such as the traveling wave profile, Walker breakdown, domain wall width, and velocity across both steady and precessional regimes. The results show that nonlinear viscous damping significantly influences domain wall motion, altering velocity behavior and expanding the steady propagating regime by shifting the Walker breakdown limit. In addition, the orientation of the magnetic field modulates the threshold and breakdown limits, affecting the range of steady propagation. Also, the numerical illustrations of the obtained analytical results yield a good qualitative agreement with recent observations.