Magnetoelastic and structural properties of azurite Cu3(CO3)2(OH)2 from neutron scattering and muon spin rotation

TL;DR

This study uses neutron scattering and muon spin rotation to investigate azurite's magnetic and structural properties, confirming magnetic order and revealing magnetoelastic effects suggestive of spin frustration.

Contribution

First combined neutron diffraction and muon spin rotation study confirming magnetic order and magnetoelastic effects in azurite, a classic 1D antiferromagnet.

Findings

Magnetic order is commensurate and coexists with magnetoelastic strain.

Short-range magnetic order appears below 3K, long-range order below 1.9K.

Magnetoelastic effects may indicate spin frustration in azurite.

Abstract

Azurite, Cu3(CO3)2(OH)2, has been considered an ideal example of a one-dimensional (1D) diamond chain antiferromagnet. Early studies of this material imply the presence of an ordered antiferromagnetic phase below $T_N \sim 1.9$ K while magnetization measurements have revealed a 1/3 magnetization plateau. Until now, no corroborating neutron scattering results have been published to confirm the ordered magnetic moment structure. We present recent neutron diffraction results which reveal the presence of commensurate magnetic order in azurite which coexists with significant magnetoelastic strain. The latter of these effects may indicate the presence of spin frustration in zero applied magnetic field. Muon spin rotation, $\mu$SR, reveals an onset of short-range order below 3K and confirms long-range order below $T_N$.