Abstract. Two silver ion conducting solid electrolytes, Ag2HgI4 and Ag2CdI4, representing a wide class of AgI-based halogenide superionics have been the subjects of study by means of electrical impedance spectroscopy, SEM, porosity measurements and fractal dimension analysis. Even though both materials have been obtained by the same method under strictly identical conditions they were found to exhibit certain differences at the microstructural level. Thus, by the direct measurements of porosity and density it was found that the grain boundaries are better developed in silver mercuric iodide. On the assumption that pore geometry in the materials under study displays fractal character it was shown that the fractal dimension of the pore contours is larger in the case of Ag2HgI4. These results are in agreement with electrical studies which indicated that the grain boundary capacitance in Ag2CdI4 is two orders of magnitude smaller than that of the silver mercuric iodide.
J. Phys.: Condens. Matter 20 (2008) 474211 (5pp)