Tunable resistivity of individual magnetic domain walls

TL;DR

This study experimentally investigates how the resistivity of magnetic domain walls varies with their width, revealing a 1/D^2 dependence consistent with Levy-Zhang theory, advancing understanding of current-DW interactions in spintronics.

Contribution

It provides the first experimental demonstration of the inverse square dependence of DW resistivity on wall width, with quantitative agreement to theoretical models.

Findings

Resistivity inside a domain wall depends on wall width D as 1/D^2.

Quantitative agreement with Levy-Zhang theory was achieved.

Resistivity measurements were performed in real-time during DW nucleation.

Abstract

Despite the relevance of current-induced magnetic domain wall (DW) motion for new spintronics applications, the exact details of the current-domain wall interaction are not yet understood. A property intimately related to this interaction is the intrinsic DW resistivity. Here, we investigate experimentally how the resistivity inside a DW depends on the wall width D, which is tuned using focused ion beam irradiation of Pt/Co/Pt strips. We observe the nucleation of individual DWs with Kerr microscopy, and measure resistance changes in real-time. A 1/D^2 dependence of DW resistivity is found, compatible with Levy-Zhang theory. Also quantitative agreement with theory is found by taking full account of the current flowing through each individual layer inside the multilayer stack.