Neutron study of in-plane skyrmions in MnSi thin films*

Magnetic skyrmions are vortex-like solitons that can arise in magnetic materials that have broken inversion symmetry. Micromagnetic calculations of thin epitaxial MnSi/Si films show that in-plane fields are capable of stabilizing skyrmions with their axis of symmetry pointing within the plane of the film. A polarized neutron reflectometry (PNR) study is presented that reveals the first direct evidence of this largely unexplored species of skyrmions. PNR measurements, which provide a depth profile of the magnetization, are interpreted with the aid of micromagnetic simulations. A potential well formed by the interaction with magnetic surface twists is found to play a key role in the confinement of these objects.