Chiral spin structures in antiferromagnet-ferromagnet bilayers

Chiral twists in atomic magnetic structure are seen in ferromagnets at the interface with heavy metals such as Pt and Ir, leading to topologically stable magnetic domains known as skyrmions. Such chiral magnetic objects have potential applications in magnetic memory and sensor technology.

Mn-based antiferromagnets also contain heavy elements (e.g. Pt, Ir), and this project will investigate chiral magnetic structure at the interface between such antiferromagnets and a ferromagnetic layer.

The reason for using antiferromagnets is that they provide an exchange bias at the interface with a ferromagnet that might help to stabilise skyrmions, as well as a Dzyaloshinskii-Moriya interaction that induces the chirality (R.A. Khan et al., Phys. Rev. B 98, 064413 (2018)). A current flowing through the antiferromagnet may also provide a spin torque to push the skyrmion through the ferromagnet, which would be of great fundamental and technological interest.