Finite size effect and strain present in chiral magnetic nanolayers cause them to create stable magnetic knots in their magnetic texture, known as skyrmions.  These self-assembled magnetic particles can be pushed with current densities that are a million times lower than required to the move domain walls in rack-track memories [1,2], potentially making skyrmions highly attractive for technological applications.

In this talk I will show how finite size effects influence the magnetic textures of chiral magnets.  Neutron reflectometry studies enabled use to observe the discrete unwinding of the ground state helical structure, and revealed a novel surface state important for the stability of the skyrmions phase.  Magnetometry and neutron scattering complimented by numerical simulations enable us to map out the phase diagram and provide a cautionary tale about the interpretation of topological Hall effect data.

[1] X. Z. Yu et al. Nature Comm., 3, 988 (2012).

[2] S. S. P. Parkin, et al. Science 320, 190 (2008).