Time: 2:30 - 2:30pm
Speaker: Prof Paolo Radaelli
Venue: G. O. Jones Building, Room 610
I will present the discovery of a novel form of crystalline vortices in antiferromagnetic (AFM) hematite (α-Fe2O3) epitaxial films, in which the primary whirling parameter is the non-ferroics staggered magnetisation. Remarkably, ferromagnetic (FM) topological objects known as half-skyrmions or merons with the same vorticity and winding number of the α-Fe2O3 vortices are imprinted onto an ultra-thin Co ferromagnetic over-layer by exchange proximity. Our data suggest that the vortex/meron pairs are relatively robust well beyond the Co coercive field, but can be manipulated by the application of a larger (H∥ 100mT) in-plane magnetic field H∥, giving rise to large-scale vortex-antivortex annihilation.