Magnetic and crystal structure of azurite Cu3(CO3)2(OH)2 as determined by neutron diffraction

Here we present neutron diffraction results on the mineral azurite. We have found that the crystal structure of azurite can be described in the space group P2(1), which is the next symmetric group below P2(1)/c, as found in earlier works. This small change in symmetry does not greatly influence the lattice parameters or atomic fractional coordinates, which are presented here for single-crystal diffraction refinements. The ordered magnetic moment structure of this material has been determined and is comprised of two inequivalent magnetic moments on copper sites of magnitude 0.684(14) and 0.264(16) mu(B). This result is discussed in terms of the anisotropic exchange and Dzyaloshinskii-Moriya interactions. It is found that the system is likely governed by one-dimensional behavior despite the long-range-ordered ground state. We also highlight the significance of strain in this material, which is strongly coupled to the magnetism.