Analytic Modelling of Elliptical Skyrmions

Magnetic skyrmions are chiral spin textures which are often stabilized by the inter-facial Dzyaloshinkii-Moriya interaction in heavy metal / ferromagnet multilayers. Such systems have approximate rotational symmetry, leading to rotationally invariant, circular skyrmions. Symmetry breaking due to applied fields, or due to the crystallographic structure of the material, may lead to skyrmions with a distorted shape. This distortion can modify the dynamics of skyrmions, in ways which may impact skyrmion based devices and measurements. Here we present an analytical approach to modelling the distortion of skyrmions and antiskyrmions into elliptical shapes. We then apply these results to investigate some of the consequences distortion on skyrmion dynamics. Micromagnetic simulations are used to validate and supplement the analytical approach.