Stable magnetic nanodomains engineered via Ga+-ion irradiation for deterministic sequential switching

TL;DR

This paper introduces a method to precisely control magnetic nanodomains using Ga+-ion irradiation to create engineered anisotropy landscapes, enabling deterministic and scalable magnetic switching.

Contribution

The authors develop a technique to pattern magnetic energy landscapes with nanoscale anisotropy wells for controlled domain-wall manipulation, advancing spintronic device design.

Findings

Reproducible switching of 750 nm regions demonstrated.

Analytical and simulation models predict domain-wall behavior in graded anisotropy.

Approaching the theoretical limit of 100 nm domain control.

Abstract

Precise control of magnetic domain formation at the nanoscale remains constrained by stochastic defect-mediated and unstable pinning, limiting scalability and reproducibility in spintronic architectures. Here we demonstrate that spatially engineered anisotropy gradients provide a deterministic alternative. Using focused Ga+-ion irradiation, we pattern magnetic energy landscapes containing nanoscale "anisotropy wells" that confine magnetic domain walls and enable bidirectional sequential switching without reliance on difficult-to-control material disorder. An analytical framework describing domain-wall energetics in graded anisotropy profiles yields predictive design rules for depinning and stability, which are supported by micromagnetic simulations and experiments. We realize programmable multi-domain configurations in continuous ferromagnetic films and demonstrate robust, reproducible switching of 750 nm regions, while first results for 100 nm are shown, approaching the theoretical limit set by the domain-wall width. By replacing unstable pinning with engineered energy landscapes, this anisotropy landscape establishes a scalable materials strategy for deterministic magnetic-state programming and opens a pathway toward dense, energy-efficient spintronic and reconfigurable magnetic nanodevices.