Dissipation processes in the insulating skyrmion compound Cu2OSeO3

TL;DR

This study investigates the dissipation processes and transition dynamics of the skyrmion lattice phase in Cu2OSeO3 using high-precision ac susceptibility measurements, revealing complex frequency-dependent dissipation and relaxation behaviors.

Contribution

It provides a detailed analysis of the dissipation and relaxation processes around the skyrmion lattice phase, highlighting similarities across different magnetic phase transitions in Cu2OSeO3.

Findings

Broad dissipation region at the conical-to-SkL transition with complex frequency dependence

Distribution of relaxation times intrinsic to the SkL phase

Frequency and magnetic field dependence of the SkL-to-paramagnet transition peak

Abstract

We present a detailed study of the phase diagram surrounding the skyrmion lattice (SkL) phase of Cu2OSe2O3 using high-precision magnetic ac susceptibility measurements. An extensive investigation of transition dynamics around the SkL phase using the imaginary component of the susceptibility revealed that at the conical-to-SkL transition a broad dissipation region exists with a complex frequency dependence. The analysis of the observed behavior within the SkL phase indicates a distribution of relaxation times intrinsically related to SkL. At the SkL-to-paramagnet transition a narrow first-order peak is found that exhibits a strong frequency and magnetic field dependence. Surprisingly, very similar dependence has been discovered for the first-order transition below the SkL phase, i.e. where the system enters the helical and conical state(s), indicating similar processes across the order-disorder transition.