Stabilizing current-driven steady flows of 180$^{\circ}$ domain walls in spin valves by interfacial Dzyaloshinskii-Moriya interaction

TL;DR

This paper systematically investigates how interfacial Dzyaloshinskii-Moriya interaction (iDMI) stabilizes and enhances current-driven 180° domain wall dynamics in spin valves, enabling faster and more robust magnetic nanodevices.

Contribution

It demonstrates that iDMI can significantly postpone Walker breakdown and stabilize high-velocity domain wall motion in various spin valve configurations, a novel insight for device development.

Findings

iDMI postpones Walker breakdown to practically infinity in planar-transverse polarizers.

High saturation velocity domain walls are stabilized by iDMI, enabling fast information transfer.

Precessional flow is suppressed in perpendicular polarizers due to stability beyond the Walker limit.

Abstract

Modulations of interfacial Dzyaloshinskii-Moriya interaction (iDMI) on current-driven dynamics of 180$^{\circ}$ domain walls (180DWs) in long and narrow spin valves (LNSVs) with heavy-metal caplayers are systematically investigated. We focus on LNSVs with in-plane magnetic anisotropy in their free layers. For planar-transverse polarizers (pinned layers of LNSVs), the Walker breakdown can be postponed considerably (practical infinity) by iDMI. More interestingly, the originally unstable traveling mode is also stabilized by iDMI with high saturation velocity thus serves as fast carrier of information. For parallel polarizers, the Walker limit is increased and the corresponding modifications of iDMI to wall velocity in both steady and precessional flows of 180DWs are provided. For perpendicular polarizers, precessional flow of 180DWs is absent due to the stability of stationary mode beyond the modified Walker limit. For LNSVs with perpendicular magnetic anisotropy in their free layers, similar results are obtained. Our findings open new possibilities for developing magnetic nanodevices based on 180DW propagation with low energy consumption and high robustness.