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Alexandra J. Huxtable

Publications and source records attributed to Alexandra J. Huxtable.

3 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, $v(\theta)$. 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

Deterministic field-free skyrmion nucleation at a nano-engineered injector device

Magnetic skyrmions are topological solitons that exhibit an increased stability against annihilation, and can be displaced with low current densities, making them a promising candidate as an information carrier. In order to demonstrate a viable skyrmion-based memory device, it is necessary to reliably and reproducibly nucleate, displace, detect, and delete the magnetic skyrmions. While the skyrmion displacement and detection have both been investigated in detail, much less attention has been dedicated to the study of the sub-ns dynamics of the skyrmion nucleation process. Only limited studies on the statics and above-ns dynamics have been performed, leaving still many open questions on the dynamics of the nucleation process. Furthermore, the vast majority of the presently existing studies focus on the nucleation from random natural pinning sites, or from patterned constrictions in the magnetic material itself, which limit the functionality of the skyrmion-based device. Those limitations can be overcome by the fabrication of a dedicated injector device on top of the magnetic material. In this study, we investigate the nucleation of magnetic skyrmions from a dedicated nano-engineered injector, demonstrating the reliable magnetic skyrmion nucleation at the remnant state. The sub-ns dynamics of the skyrmion nucleation process were also investigated, allowing us to shine light on the physical processes driving the nucleation.

cond-mat.mes-hall