Domain Wall Spin Dynamics in Kagome Antiferromagnets

TL;DR

This study investigates slow spin dynamics in Fe-based kagome antiferromagnets caused by domain walls and free spins, revealing a transition from individual spin flips to cooperative behavior at very low temperatures.

Contribution

It introduces new insights into domain wall behavior and slow spin dynamics in kagome antiferromagnets with strong local anisotropy and low connectivity.

Findings

Observation of slow spin dynamics due to domain walls intersecting kagome planes.

Transition from exchange-released spin-flips to cooperative behavior at low temperatures.

Identification of a domain structure of independent magnetic grains potentially common in frustrated magnets.

Abstract

We report magnetization and neutron scattering measurements down to 60 mK on a new family of Fe based kagome antiferromagnets, in which a strong local spin anisotropy combined with a low exchange path network connectivity lead to domain walls intersecting the kagome planes through strings of free spins. These produce unfamiliar slow spin dynamics in the ordered phase, evolving from exchange-released spin-flips towards a cooperative behavior on decreasing the temperature, probably due to the onset of long-range dipolar interaction. A domain structure of independent magnetic grains is obtained that could be generic to other frustrated magnets.