Magnetic correlations in deuteronium jarosite, a model S=5/2 Kagome antiferromagnet

TL;DR

This study investigates the magnetic properties of deuteronium jarosite, a kagome lattice antiferromagnet with S=5/2 spins, revealing strong in-plane antiferromagnetic interactions, short-range correlations, and a spin-glass transition at low temperature.

Contribution

It provides detailed experimental insights into magnetic correlations and excitations in a model S=5/2 kagome antiferromagnet, combining susceptibility, specific heat, and neutron diffraction data.

Findings

Strong in-plane antiferromagnetic exchange with heta_CW ≈ -1500 K

Spin-glass transition observed at T_f=13.8 K

Short-range magnetic correlations with \xsi≈19 Å at 1.9 K

Abstract

Deuteronium jarosite, (D_3O)Fe_3(SO_4)_2(OD)_6, contains a kagome lattice of Heisenberg spins, S=5/2, with a coverage of 97+-1%. DC and AC susceptibility measurements show strong in-plane antiferromagnetic exchange (\theta_CW=-1500+-300K) and a spin-glass transition at T_f=13.8 K, while the magnetic contribution to the specific heat below T_f rises with T as T^2, characteristic of two-dimensional propagating modes. Powder neutron diffraction reveals short-range magnetic correlations (\xsi=19+-2 \AA) with a wavevector corresponding to the \sqrt{3}x\sqrt{3} spin structure at 1.9 K.