The structural and electrical characterizations of mechanically-milled (MM) amorphous fast ionic conductors (a-FICs), viz. xAgI (100-x)[0.67 Ag_2 O-0.33V_2O_5] (x = 40, 50, 55 and 70) have been reported. The amorphisation is restricted only to the compositions which are well within the glass forming region and all samples are found to be highly agglomerated and X-ray amorphous in nature. The frequency dependent ac conductivity, sigma(omega), of the amorphous samples investigated in the frequency range 5Hz -13 MHz and temperature range 100- 350 K shows a dc conductivity regime at low frequencies and a dispersive regime at higher frequencies. The spectra can be described by the Jonscher power law (JPL), simga(omega) = sigma_dc +A(T) omega_n. However, the values sigma_dc (T) and A(T) both show two distinct Arrhenius regions and n (< 1) is found to be temperature dependent, i.e., decreasing with increasing temperature.
تحميل البحث