‘Microscopy and Magnetic Materials: Exploring Energy Landscapes at the Nanoscale’.

Join Oxford Materials alumna Professor Amanda Petford-Long on this fascinating journey through the nanoscale world, and find out more about her world-class research at Argonne National Laboratory and Northwestern University.

Abstract:
As the dimensions of magnetic materials decrease to the nanoscale, novel distributions of spin can be created, which are determined by the balance between the energy terms that control behaviour. We are exploring the formation of these novel distributions and ways to control them through gaining an understanding of the local energy landscape of the nanostructures.

We use a combination of Lorentz transmission electron microscopy (LTEM) and in-situ experiments, together with micromagnetic simulations, to image the micromagnetic behaviour at the sub-micron scale in a range of magnetic nanostructures. Quantitative analysis of the Lorentz TEM data has been carried out using the transport of intensity equation (TIE) approach, which we have extended to allow us to visualize the magnetic structure in three dimensions. By comparing these data with the results of simulations, we are able to gain a fuller understanding of the various energy terms that contribute to the behaviour that we observe.

In this talk I will focus on skyrmions, which are chiral spin structures, and artificial spin ices consisting of arrays of nanoscale magnetic elements patterned on periodic and quasicrystalline 2D lattices.