Magnetoelastic and structural properties of azurite Cu_3(CO_3)_2(OH)_2 from neutron scattering and muon spin rotation

摘要

Azurite, Cu_3(CO_3)_2(OH)_2, has been considered an ideal example of a one-dimensional diamond chain antiferromagnet. Early studies of this material imply the presence of an ordered antiferromagnetic phase below T_N～ 1.9 K while magnetization measurements have revealed a 1/3 magnetization plateau. To the best of our knowledge, 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 reveals an onset of short-range order below 3 K and confirms long-range order below T_N.