Reduction of threshold current density for current-driven domain wall motion by shape control

TL;DR

This study demonstrates that by controlling the shape of Ni81Fe19 nanowires, the threshold current density for domain wall motion can be significantly reduced, confirming theoretical predictions about the role of magnetic anisotropy and wire dimensions.

Contribution

The paper experimentally shows that magnetic shape anisotropy influences the threshold current density, enabling a reduction by half through shape control, aligning with theoretical models.

Findings

Threshold current density increases with Kperp*l.

Shape control can halve the threshold current density.

Experimental validation of theoretical predictions.

Abstract

We investigated the aspect ratio (thickness/width) dependence of the threshold current density required for the current-driven domain wall (DW) motion for the Ni81Fe19 nanowires. It has been shown theoretically that the threshold current density is proportional to the product of the hard-axis magnetic anisotropy Kperp and the DW width lamda. (Phys. Rev. Lett. 92, 086601 (2004).) We show experimentally that Kperp can be controlled by the magnetic shape anisotropy in the case of the Ni81Fe19 nanowires, and that the threshold current density increases with an increase of Kperp*l. We succeeded to reduce the threshold current density by half by the shape control.