SCIENCE SPIN-OFFS

[dockzef]

Metastable skyrmions with various topologies in an ultrathin magnetic film. I. Formation and stability

Levente Rózsa, Krisztián Palotás, András Deák, Eszter Simon, Rocio Yanes, László Udvardi, László Szunyogh, Ulrich Nowak

(Submitted on 22 Sep 2016)

We observe metastable localized spin configurations with topological charges ranging from Q=-3 to Q=2 in a (Pt0.95Ir0.05)/Fe bilayer on Pd(111) surface by performing spin dynamics simulations, using a classical Hamiltonian parametrized by ab initio calculations. We demonstrate that the frustration of the isotropic exchange interactions is responsible for the creation of these various types of skyrmions. The Dzyaloshinsky--Moriya interaction present due to the breaking of inversion symmetry at the surface energetically favors skyrmions with Q=-1, distorts the shape of the other objects, and defines a preferred orientation for them with respect to the underlying lattice.

http://arxiv.org/abs/1609.07012

Well for flippin sake it about damn time someone owned up to isotropic exchange interactions yielding various outcomes. Really

Skyrmions with Q = -3,-2 in Table II have a positive binding energy; due to this reason, they can easily split into constituents with Q = -1. Higher-order skyrmions represent a lower magnetization di?erence with respect to the ?eld-polarized state than two or three individual skyrmions; therefore, the positive binding energy slightly decreases as the external ?eld is increased due to the energy gain from the Zeeman term; see the row for Q = -2