Tension-free Dirac strings and steered magnetic charges in 3D artificial spin ice

TL;DR

This study demonstrates a 3D artificial spin ice system with tension-free Dirac strings and mobile magnetic charges at room temperature, enabling controlled data transport and storage in magnetic networks.

Contribution

It introduces a micromagnetic model of a 3D spin ice with tension-free Dirac strings and unbound magnetic charges operable at room temperature, advancing magnetic data applications.

Findings

Magnetic charges are mobile at room temperature due to tension-free Dirac strings.

Global magnetic fields can steer magnetic charges directionally.

Mobility threshold is 2 eV lower than unbinding energy, enabling charge movement.

Abstract

3D nano-architectures present a new paradigm in modern condensed matter physics with numerous applications in photonics, biomedicine, and spintronics. They are promising for the realisation of 3D magnetic nano-networks for ultra-fast and low-energy data storage. Frustration in these systems can lead to magnetic charges or magnetic monopoles, which can function as mobile, binary information carriers. However, Dirac strings in 2D artificial spin ices bind magnetic charges, while 3D dipolar counterparts require cryogenic temperatures for their stability. Here, we present a micromagnetic study of a highly-frustrated 3D artificial spin ice harboring tension-free Dirac strings with unbound magnetic charges at room temperature. We use micromagnetic simulations to demonstrate that the mobility threshold for magnetic charges is by $\SI{2}{eV}$ lower than their unbinding energy. By applying global magnetic fields, we steer magnetic charges in a given direction omitting unintended switchings. The introduced system paves a way towards 3D magnetic networks for data transport and storage