# A Tuneable Magnetic Domain Wall Conduit Regulating Nanoparticle Diffusion

## TL;DR

This paper presents a versatile magnetic channel system that can precisely confine and control the diffusion of nanoparticles in water, enabling reversible particle organization and pattern formation.

## Contribution

It introduces a tunable magnetic conduit using movable Bloch walls for controlled nanoparticle confinement and organization.

## Key findings

- Magnetic potential stiffness is adjustable via field amplitude.
- Particles form single files and parallel stripes under magnetic confinement.
- The system allows reversible and precise control of particle arrangements.

## Abstract

We demonstrate a general and robust method to confine on a plane strongly diffusing submicrometer particles in water by using size tunable magnetic channels. These virtual conduits are realized with pairs of movable Bloch walls (BWs) located within an epitaxially grown ferrite garnet film. We show that, once inside the magnetic conduit, the particles experience an effective local parabolic potential in the transverse direction, while freely diffusing along the conduit. The stiffness of the magnetic potential is determined as a function of field amplitude which varies the width of the magnetic channel, and precise control of the degree of confinement is demonstrated by tuning the applied field. The magnetic conduit is then used to realize single files of non-passing particles and to induce periodic condensation of an ensemble of particles into parallel stripes in a completely controllable and reversible manner.