arXiv subjects

Alexander Welbourne

Publications and source records attributed to Alexander Welbourne.

3 recordsLinked to original sources

arXiv2024

RingSim- An Agent-based Approach for Modelling Mesoscopic Magnetic Nanowire Networks

We describe 'RingSim', a phenomenological agent-based model that allows numerical simulation of magnetic nanowire networks with areas of hundreds of micrometers squared for durations of hundreds of seconds; a practical impossibility for general-purpose micromagnetic simulation tools. In RingSim, domain walls (DWs) are instanced as mobile agents which respond to external magnetic fields, and their stochastic interactions with pinning sites and other DWs are described via simple phenomenological rules. We first present a detailed description of the model and its algorithmic implementation for simulating the behaviours of arrays of interconnected ring-shaped nanowires, which have previously been proposed as hardware platforms for unconventional computing applications. The model is then validated against a series of experimental measurements of an array's static and dynamic responses to rotating magnetic fields. The robust agreement between the modelled and experimental data demonstrates that agent-based modelling is a powerful tool for exploring mesoscale magnetic devices, enabling time scales and device sizes that are inaccessible to more conventional magnetic simulation techniques.

cond-mat.mes-hall↗

arXiv2022

Reconfigurable Reservoir Computing in a Magnetic Metamaterial

In-materia reservoir computing (RC) leverages the intrinsic physical responses of functional materials to perform complex computational tasks. Magnetic metamaterials are exciting candidates for RC due to their huge state space, nonlinear emergent dynamics, and non-volatile memory. However, to be suitable for a broad range of tasks, the material system is required to exhibit a broad range of properties, and isolating these behaviours experimentally can often prove difficult. By using an electrically accessible device consisting of an array of interconnected magnetic nanorings -- a system shown to exhibit complex emergent dynamics -- here we show how reconfiguring the reservoir architecture allows exploitation of different aspects the system's dynamical behaviours. This is evidenced through state-of-the-art performance in diverse benchmark tasks with very different computational requirements, highlighting the additional computational configurability that can be obtained by altering the input/output architecture around the material system.

cond-mat.mes-hall↗

arXiv2017

Fabrication, detection and operation of a three-dimensional nanomagnetic conduit

Three-dimensional (3D) nanomagnetic devices such as the vertical racetrack memory have attracted a huge interest due to their potential for memory and logic applications. However, their implementation has not been realised due to great challenges regarding fabrication and characterisation of 3D nanostructures. Here, we show a 3D nanomagnetic system created by 3D nano-printing and physical vapour deposition, which acts a conduit for domain walls. Domains formed at the substrate level are injected into a 3D nanowire, where they are controllably trapped using vectorial magnetic fields. A dark-field magneto-optical method for parallel, independent measurement of different regions in individual 3D nanostructures is also demonstrated. This work opens a new route for the advanced study and exploitation of 3D nanomagnetic systems.

cond-mat.mes-hall↗