Synthesis and characterization of single crystals of the spin-1/2 kagome-lattice antiferromagnets ZnxCu4-x(OH)6Cl2

The Zn-paratacamite family, ZnxCu4-x(OH)(6)Cl-2 for x >= 0.33, is an ideal system for studying spin-1/2 frustrated magnetism in the form of antiferromagnetic Cu2+ kagome planes. Here we report a new synthesis method by which high-quality millimeter-sized single crystals of Zn-paratacamite have been produced. These crystals have been characterized by metal analysis, x-ray diffraction, neutron diffraction, and thermodynamic measurements. The x = 1 member of the series displays a magnetic susceptibility that is slightly anisotropic at high temperatures with chi(c) > chi ab. Neutron and synchrotron x-ray diffraction experiments confirm the quality of these x = 1 single crystals and indicate no obvious structural transition down to temperatures of T 2 K.