Domain wall automotion in three-dimensional magnetic helical interconnectors

TL;DR

This paper demonstrates a novel 3D magnetic interconnector utilizing geometry-driven domain wall automotion, enabling efficient unidirectional magnetic information transfer in three-dimensional structures, with potential for high-speed operation.

Contribution

It introduces a new 3D helical domain wall conduit fabricated with nanoprinting and vapor deposition, showing how geometry induces automotion and influences magnetic energy gradients.

Findings

Robust unidirectional domain wall motion observed in 3D spirals.

Large thickness gradients are key to domain wall automotion.

Predicted high domain wall velocities reaching the Walker limit.

Abstract

The fundamental limits currently faced by traditional computing devices necessitate the exploration of new ways to store, compute and transmit information. Here, we propose a three-dimensional (3D) magnetic interconnector that exploits geometry-driven automotion of domain walls (DWs), for the transfer of magnetic information between functional magnetic planes. By combining state-of-the-art 3D nanoprinting and standard physical vapor deposition, we prototype 3D helical DW conduits. We observe the automotion of DWs by imaging their magnetic state under different field sequences using X-ray microscopy, observing a robust unidirectional motion of DWs from the bottom to the top of the spirals. From experiments and micromagnetic simulations, we determine that the large thickness gradients present in the structure are the main mechanism for 3D DW automotion. We obtain direct evidence of how this tailorable magnetic energy gradient is imprinted in the devices, and how it competes with pinning effects due to local changes in the energy landscape. Our work also predicts how this effect could lead to high DW velocities, reaching the Walker limit during automotion. This work provides new possibilities for efficient transfer of magnetic information in three dimensions.