Synthesis and characterization of single crystals of the spin-1/2 kagome-lattice antiferromagnets Zn[subscript x]Cu[subscript 4-x](OH)[subscript 6]Cl[subscript 2]

Abstract

The Zn-paratacamite family, ZnxCu4-x(OH)6Cl2 for x [greater than or equal to]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 χc>χab. 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.