Colossal topological Hall effect at the transition between isolated and lattice-phase interfacial skyrmions

TL;DR

This study demonstrates that the topological Hall effect can be significantly enhanced at the phase boundary between isolated skyrmions and a disordered skyrmion lattice in Ir/Fe/Co/Pt heterostructures, highlighting the influence of skyrmion stability and configuration.

Contribution

It reveals how skyrmion phase boundaries dramatically amplify the topological Hall effect in thin film heterostructures.

Findings

Topological Hall resistivity increases by up to three orders of magnitude.

Skyrmion stability and configuration are key factors in the effect's magnitude.

Power-law enhancement linked to chiral spin fluctuations at phase boundaries.

Abstract

The topological Hall effect is used extensively to study chiral spin textures in various materials. However, the factors controlling its magnitude in technologically-relevant thin films remain uncertain. Using variable temperature magnetotransport and real-space magnetic imaging in a series of Ir/Fe/Co/Pt heterostructures, here we report that the chiral spin fluctuations at the phase boundary between isolated skyrmions and a disordered skyrmion lattice result in a power-law enhancement of the topological Hall resistivity by up to three orders of magnitude. Our work reveals the dominant role of skyrmion stability and configuration in determining the magnitude of the topological Hall effect.