Probing strain effects on an unusual skyrmion lattice

Solid state systems possessing non-trivial topological magnetic structures are of interest in the context of spintronic and memory applications as well as the fundamental study of quantum materials with a Berry phase. A fascinating example of such a system is the correlated oxide, SrFeO3, which is speculated to host a lattice of skyrmions (emergent magnetic monopoles). The skyrmions of SrFeO3 are expected to be small, meaning high density memories are feasible. Usually skyrmion lattices arise due to magnetic frustration or, more commonly, a non-centrosymmetric structure. SrFeO3 is centrosymmetric and has no frustration. The origin of the skyrmion lattice in SrFeO3 has not been proved experimentally but is theorised to stem from a modified double exchange with negative charge transfer. Out of this theory comes a predicted relationship between the helimagnetic angle, which can be determined by neutron scattering scattering, and features of the electronic structure. Epitaxial strain in thin films is an ideal control platform to test this relationship. Pinpointing the origin of this unique type of skyrmion lattice is the first step towards understanding how to manipulate it and eventually integrate these materials in new transformative technologies. We will analyse SrFeO3 under both compressive and tensile strain. As a complement and feasibility test, we will also study an exfoliated membrane of SrFeO3 with no native strain.