Magnetic skyrmion lattices in heavy fermion superconductor UPt3

TL;DR

This paper explores magnetic skyrmion lattices in the heavy fermion superconductor UPt3, revealing a new class of flux-carrying solutions with unique properties and experimental relevance.

Contribution

It introduces magnetic skyrmion solutions in UPt3's Ginzburg--Landau theory, showing their stability, lattice formation, and agreement with experimental magnetic induction behavior.

Findings

Existence of skyrmion solutions with two units of magnetic flux.

Skyrmions form a robust triangular lattice due to repulsive interactions.

Magnetic induction near Hc1 increases as (H-Hc1)^2, matching experiments.

Abstract

Topological analysis of nearly SO(3)_{spin} symmetric Ginzburg--Landau theory, proposed for UPt$_{3}$ by Machida et al, shows that there exists a new class of solutions carrying two units of magnetic flux: the magnetic skyrmion. These solutions do not have singular core like Abrikosov vortices and at low magnetic fields they become lighter for strongly type II superconductors. Magnetic skyrmions repel each other as $1/r$ at distances much larger then the magnetic penetration depth $\lambda$, forming a relatively robust triangular lattice. The magnetic induction near $H_{c1}$ is found to increase as $(H-H_{c1})^{2}$. This behavior agrees well with experiments.