Research programme

Caption: Schematic representation of a vector field (visualised by the cones) in a finite difference discretisation: the magnetisation vector field is continuous in space in the micromagnetic model, but discretised into cubes (shown as transparent cubes in the figure) to be solvable numerically. The vector field is assumed to be constant within each cube and represented by a single cone in the figure. An equation of motion is known to compute how the vector field is changing over time. In each time step, a number of so-called effective fields have to be computed that enter the equation of motion. Most of these are local and short-range and thus no particular challenge for parallelisation. An important part of this project is the efficient computation of the long-range dipolar interaction, which we are familiar with from handling bar and fridge magnets: opposite magnetic poles attract each other.

Research programme

Computational Micromagnetics is a widely used technique to predict and improve the behaviour of magnetic devices, for example in the data storage and sensing industry. Spintronics, Magnonics, and most recently Skyrmions [1] are particular directions of development in nanotechnology research that offer opportunities to replace electronics as the technology that drives computing and can be simulated using micromagnetic models.

As research moves into assembly of logic units and combination of these into larger systems and devices, the need to simulate large-scale magnetic nanostructures becomes more pressing. Scientists have made use of multi-core CPUs in shared memory systems [2] to accelerate single-core computations, and codes have been developed that take advantage of GPUs [3]. These approaches, while great progress, are limited by a number of cores available in a single machine and available RAM on the GPU, respectively, and cannot provide the large system simulations.

In this project, we will develop, evaluate and use simulation software that allows to carry out MPI-based large-scale computation which can run on today's state of the art High Performance Computing (HPC) systems such as local Linux clusters and national high-end computing hardware, including the UK's supercomputer Archer [4]. Focus will be on solving the micromagnetic problem using finite differences and optimise scaling behaviour of the code across a large number of cores. Significant effort will go into the development of a scalable computation of the long-range demagnetisation field and its MPI implementation.

We will use modern software engineering approaches such as test-driven development, continuous integration and release the tool as open source to benefit all of the micromagnetic communities in academia and industry (see for example [5] for the wealth of micromagnetic applications).

We will also apply the tool to simulate micromagnetic structures together with national and international collaborators, who often carry out experiments and want to explore devices, and benefit from the simulation in interpreting and guiding their work.

For this project, we are looking for a computer scientist with interest in science and computational science, or a mathematician/physicist/engineer/... with interest in programming and software engineering, who can work independently and as part of a team.

[1] http://www.southampton.ac.uk/~fangohr/blog/2015-what-is-it-with-these-skyrmions.html

[2] OOMMF, http://math.nist.gov/oommf/

[3] Mumax, http://mumax.github.io

[4] http://archer.ac.uk

[5] OOMMF citations, http://math.nist.gov/oommf/oommf_cites.html

Details

This project is part of the 4-year EPSRC Centre for Doctoral Training in Next Generation Computational Modelling which comes with 1 year of (mostly) taught training (programming, software engineering, applied mathematics, ...) and an above average support package. Please see the project description NGCM-0055 and generic information about the doctoral training programme at http://ngcm.soton.ac.uk and http://ngcm.soton.ac.uk/programme/index.html.

Application deadline: applications are invited as soon as possible.

Funding: This project can be funded (fees and studentship) through the Centre for Doctoral Training in Next Generation Computational Modelling. The project will start in September 2016, but do apply now.

Eligibility: Please see http://www.ngcm.soton.ac.uk/studentships.html

Contact and Applications: Please contact Hans Fangohr <fangohr@soton.ac.uk> for informal queries, expressions of interest or applications. To apply formally, please follow instructions at http://ngcm.soton.ac.uk/apply.html.

Last updated: 10 November 2015

Questions?

If you wish to discuss any details of the project informally, please contact Hans Fangohr, Email: Fangohr@soton.ac.uk, Tel: +44 (0) 2380 598345, @ProfCompMod.