Dr Joseph Barker is an Associate Professor of Physics at the University of Leeds, specialising in theoretical and computational condensed matter physics. His research focuses on understanding magnetic materials and nonequilibrium spin phenomena across atomic and mesoscopic scales, with particular emphasis on the microscopic mechanisms governing spin dynamics, transport, and dissipation.

His research interests include atomistic spin dynamics, spintronics, ultrafast magnetism, antiferromagnetic materials, magnonics, spin caloritronics, and the theory and simulation of magnetic materials. A central theme of his work is the development and application of computational models that connect microscopic magnetic interactions with experimentally observable dynamical and transport behaviour. This includes the study of thermally driven spin dynamics, angular-momentum transfer, magnetic excitations, and the response of complex magnetic systems to ultrafast and nonequilibrium perturbations.

In this talk I will introduce atomistic approaches to modelling magnetism. I will begin with the theoretical background including the justification and derivation of an atomic model and the limitations of such a model. I will discuss how to parametrise an atomic model from both a multiscale approach (from first principles) and from experiments. I will explain magnetocrystalline anisotropy, Dzyaloshinskii-Moriya interaction and dipolar interaction with an explanation of the underlying physics and the magnetic behaviour they enable on the atomic scale. The key Landau-Lifshitz-Gilbert equation will be introduced as well as the concept of coupling to a heat bath to enable finite temperature studies. A range of examples will be given of properties that can be calculated in atomic methods for comparison to experiments, including basic thermodynamic quantities as well as magnon transport properties.