Frequency dependent transport characteristics of mechanochemically synthesized PbSnF4

A high anion conducting PbSnF4 has been prepared through ball-milling technique from the starting materials of PbF2 and SnF2 in the ratio 1:1 at room temperature as well as by the precipitation route from aqueous solution of Pb(NO3)(2) and SnF2-X-ray diffraction method reveals the formation of alpha-PbSnF4 and the differential scanning calorimetry technique shows all allotropic phase transformations of the material. The temperature and frequency dependence of electrical conductivity have been investigated by means of impedance spectroscopy. The conductivity of a ball-milled PbSnF4 sample was around 1 X 10(-4) S/cm at 303 K and the electrical conductivity study carried out in the temperature range 303-513 K shows an activation energy of 0.23 eV. The average grain size and the strain factor were calculated from the line width of XRD patterns and their correlation with the conductivity value has been investigated. The real part of the frequency dependent conductivity exhibits a simple power law feature and the dimensionless frequency exponent n has been determined. A low frequency dispersion of the conductivity was observed due to the space charge polarisation, which resulted from the high ionic conductivity of the material. Various electrical parameters as a function of temperature have been analysed in different complex planes. The frequency dependent plots of M and Z show that the conductivity relaxation is non-Debye in nature. The conductivity relaxation time has been estimated from the modulus spectra and the activation energy responsible for relaxation has been evaluated.