Anisotropy in Ba2Cu3O4Cl2 single crystals grown by the traveling solvent floating zone method

Magnetic and electrical properties of layered copper oxychloride Ba2Cu3O4O2 single crystals are measured. Single crystal growth of Ba2Cu3O4Cl2 by the traveling solvent floating zone method is attempted using Ba3Cu2O4Cl2 as solvent. By optimization of the growth conditions, large single crystals of (phi 5 mm x 30 mm) of Ba2Cu3O4Cl2 are grown. The resistivity with the current parallel to the c-axis is 10(2)-10(3) times larger than that with the current perpendicular to the a-axis. The temperature dependence of the dielectric spectrum for each direction is measured and analyzed by using the Debye model. The spectrum width, which is related to the effective number of electrons (n/m), does not show an appreciable dependence on temperature. The characteristic frequencies at which the dielectric constant changes, which are related to the dissipation (y), increase with warming. The temperature dependence is almost the same as the resistivity curve. This indicates that the hopping process dominates both DC- and AC-type electrical transport. The spectrum width with the electric field parallel to the a-axis is 30 times larger than that with the electric field parallel to the c-axis. On the other hand, the characteristic frequencies do not show an appreciable dependence on electric field direction. (c) 2006 Elsevier B.V. All rights reserved.