Abstract
A new silver-cobalt arsenate, Ag4Co7(AsO4)(6), is synthesized by solid state reaction method and characterized by X-ray diffraction and impedance spectroscopy. The phase crystallizes in the monoclinic space group C2/m with a = 10.755(2) angstrom, b = 14.937(2) angstrom, c = 6.731(2) angstrom, and beta = 106.17(3)degrees. The structure is described as a three-dimensional anionic framework having interconnecting tunnels running along [100] and [010]. The former contains the silver cations. Ball milling is used as mechanical means to reduce the particles sizes of the as synthesized powder. At the optimal sintering temperature of 1173 K, dense ceramics (96% of the relative density) are obtained. Their microstructure is characterized by scanning electron microscopy. The conductivity of the ceramics is studied at different relative densities over a temperature interval from 437 to 773 K. The high conductivity at 210 degrees C (3.3 x 10 (5) S cm (1)) and the activation energy (Ea = 0.45 eV) show that Ag4Co7(AsO4)(6) is a fast ionic conductor. (C) 2013 Elsevier B. V. All rights reserved.