Polarized neutron scattering studies of the kagome lattice antiferromagnet KFe3(OH)6(SO4)2

TL;DR

This study uses polarized neutron scattering to investigate spin excitations in the kagome lattice antiferromagnet KFe3(OH)6(SO4)2, revealing spin gaps and fluctuations that highlight its potential for exploring 2D XY universality.

Contribution

First polarized neutron scattering analysis of spin dynamics in KFe3(OH)6(SO4)2, identifying spin gaps and in-plane fluctuations related to its XY symmetry.

Findings

Identified two spin gaps associated with in-plane and out-of-plane excitations.

Observed in-plane spin fluctuations with XY symmetry above T_N.

Jarosite is a promising candidate for studying 2D XY universality class.

Abstract

We report polarized neutron scattering studies of spin-wave excitations and spin fluctuations in the S=5/2 kagome lattice antiferromagnet KFe3(OH)6(SO4)2 (jarosite). Inelastic polarized neutron scattering measurements at 10 K on a single crystal sample reveal two spin gaps, associated with in-plane and out-of-plane excitations. The polarization analysis of quasi-elastic scattering at 67 K shows in-plane spin fluctuations with XY symmetry, consistent with the disappearance of the in-plane gap above the Neel temperature T_N = 65 K. Our results suggest that jarosite is a promising candidate for studying the 2D XY universality class in magnetic systems.