Tracking random walk of individual domain walls in cylindrical nanomagnets with resistance noise

TL;DR

This study demonstrates that resistance noise measurements can track the stochastic diffusive motion of individual domain walls in cylindrical nanomagnets, revealing their kinetic states and potential for memory device applications.

Contribution

The paper introduces a novel method to monitor the random walk of domain walls in nanowires via resistance noise, providing insights into their stochastic dynamics.

Findings

Domain walls exhibit diffusive random walk behavior.

Resistance noise can detect the kinetic state of domain walls.

Method enables potential applications in domain wall memory devices.

Abstract

The stochasticity of domain wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time-dependence of noise reveals a diffusive random walk of the DWs with an universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.