ac electrical conduction and dielectric properties in (Na2O) –(Fe2O3)0.5-x - (B2O3)0.5 glass systems

In the present study, a series of borate glasses with the composition (Na 2 O) x – (Fe 2 O 3 ) 0.5−x - (B 2 O 3 ) 0.5 where x = 0.05, 0.1, 0.15, 0.20 and 0.25 were prepared by quenching technique. The amorphous nature of the samples has been confirmed by the XRD studies. The ac electrical conduction over a wide range of temperature and frequency was studied. As temperature increases the dielectric properties were found to enhance and with increment in frequency they were found to decrease. The complex impedance analysis (cole-cole plot) for different samples have been analysed and studied. The high temperature ac conductivity data has been analysed by Mott’s small polaron hopping model (SPH). Activation energy passed through maximum and conductivity passed through minimum at 0.20 concentrations of sodium oxide which has been ascribed to the switch over of conduction process, taking place at 0.20 molar fraction of alkali ions, primarily from polaronic to ionic in the present series of glasses.