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Bryan J. Hickey

Publications and source records attributed to Bryan J. Hickey.

2 recordsLinked to original sources

Anisotropic domain wall velocity profiles in the creep regime: the interplay of chiral damping, stiffness and Dzyaloshinskii-Moriya interaction

The asymmetric expansion of magnetic bubble domains in ultrathin ferromagnets provides a powerful route to probe the interfacial Dzyaloshinskii-Moriya interaction (DMI). While conventional analyses rely on domain wall velocities measured along selected directions as a function of in-plane field, recent approaches have highlighted the additional insight contained in the angular dependence of the velocity, $v(θ)$. Here, we develop an extended angular creep model that incorporates both the dispersive domain wall stiffness and a chirality-dependent prefactor associated with chiral damping. This generalization captures the full anisotropic dynamics of domain wall motion around a bubble domain. We show that these contributions significantly modify the angular velocity profile and can lead to features not accessible within existing models. Our results establish a more complete framework for interpreting creep-driven domain expansion and provide improved sensitivity for the quantitative extraction of DMI and chiral dynamical effects.

cond-mat.mes-hall

Magnetic domain wall curvature effects on the velocity in the creep regime

We study the effect of magnetic domain wall curvature on its dynamics in the creep regime in systems displaying Dzyaloshinskii-Moriya interaction (DMI). We first derive an extended creep model able to account for the finite curvature effect in magnetic bubble domain expansion. We then discuss the relative importance of this effect and discuss its dependence on the main magnetic and disorder parameters. We show this effect can be easily measured in Pt/Co multi layer samples, reporting a strong velocity reduction below a sample dependent threshold value of the magnetic bubble radius. We finally show, both theoretically and experimentally, how the radius of magnetic bubbles can have a strong impact on the reproducibility of DMI measurements.

cond-mat.mes-hall