The properties of isolated chiral skyrmions in thin magnetic films

TL;DR

This paper combines experimental and theoretical approaches to characterize isolated chiral skyrmions in thin magnetic films, revealing their stability conditions and universal properties across various condensed matter systems.

Contribution

It provides a comprehensive description of isolated skyrmions in thin layers, linking their properties to broken mirror symmetry in diverse materials.

Findings

Skyrmions exist within specific magnetic field ranges.

Theoretical models accurately describe skyrmion stability.

Skyrmions share properties across different noncentrosymmetric systems.

Abstract

Axisymmetric solitonic states (chiral skyrmions) have been predicted theoretically more than two decades ago. However, until recently they have been observed in a form of skyrmionic condensates (hexagonal lattices and other mesophases). In this paper we report experimental and theoretical investigations of isolated chiral skyrmions discovered in PdFe/Ir(111) bilayers two years ago (Science 341 , 636 (2013)). The results of spin-polarized scanning tunneling microscopy analyzed within the continuum and discrete models provide a consistent description of isolated skyrmions in thin layers. The existence region of chiral skyrmions is restricted by strip-out instabilities at low fields and a collapse at high fields. We demonstrate that the same equations describe axisymmetric localized states in all condensed matter systems with broken mirror symmetry, and thus our findings establish basic properties of isolated skyrmions common for chiral liquid crystals, different classes of noncentrosymmetric magnets, ferroelectrics, and multiferroics.