Frequency dependent conduction characteristics of mechanochemically synthesized NaSn<inf>2</inf>F<inf>5</inf>

Sodium pentafluorodistannite has been synthesized through high-energy ball milling as well as by solid-state reaction method and characterized through XRD and DSC techniques. The electrical conductivity and modulus characteristics of the system are investigated in the temperature range from 373 K to 473 K by means of impedance spectroscopy. The conductivity of the ball-milled sample is about one order of magnitude higher compared to the sample prepared by solid-state reaction method. The frequency dependent conductivity of the present system shows the power law feature. The real part of dielectric permittivity shows a huge value at lower frequencies due to the presence of space charge polarization. The activation energy responsible for relaxation calculated from the modulus spectra is found to be almost the same as the value obtained from temperature variation of dc conductivity. The conductivity and modulus spectra of the present system show scaling behavior, which means that σ*(ω) and M″(ω) isotherms successfully collapse to a single master curve indicating temperature independent relaxation behavior. © 2009 Elsevier B.V. All rights reserved.