It is well documented that subjecting perpendicular magnetic films that exhibit the interfacial Dzyaloshinskii-Moriya interaction to an in-plane magnetic field results in a domain wall (DW) energy σ, which is highly anisotropic with respect to the orientation of the DW in the film plane Θ. We demonstrate that this anisotropy has a profound impact on the elastic response of the DW as characterized by the surface stiffness σ[over ˜](Θ)=σ(Θ)+σ^{''}(Θ) and evaluate its dependence on the length scale of deformation. The influence of stiffness on DW mobility in the creep regime is assessed, with analytic and numerical calculations showing trends in σ[over ˜] that better represent experimental measurements of domain wall velocity in magnetic thin films compared to σ alone. Our treatment provides experimental support for theoretical models of the mobility of anisotropic elastic manifolds and makes progress toward a more complete understanding of magnetic domain wall creep.

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We characterize asymmetric growth of magnetic bubble domains in perpendicularly magnetized Co/Ni multi-layers grown on PtxIr1−x seedlayers by application of perpendicular and in-plane magnetic fields. Using a refined model of domain wall creep that incorporates contributions from the anisotropic elastic energy, ε, and a chirality-dependent prefactor, v0, we elucidate factors that govern the mobility of Dzyaloshinskii domain walls as a function of seedlayer composition. The interfacial Dzyaloshinskii-Moriya Interaction magnitude is found to decrease monotonically with xIr, which is independently confirmed by Brillouin light scattering (BLS). Moreover, the persistence of significant asymmetry in velocity curves across the full composition range supports previous assertions that a chirality-dependent attempt frequency akin to chiral damping could play a critical role in the observed trends. This work helps resolve fundamental questions about the factors governing Dzyaloshinskii DW creep and demonstrates varying Pt-Ir seedlayer composition as a method to tune DMI.

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