Transport properties of Li2O-MnO2-B2O3 glasses

Lithium borate containing MnO2 glasses have been synthesized by melt quenching technique over a wide composition range. Frequency and temperature dependent conductivity measurements have been carried out in the range of 10 Hz to 13 MHz and at a temperature range of 298 K-523 K respectively. The impedance plots show only one semicircle indicating the presence of one type of conduction mechanism. The analysis of dc conductivity show that the conductivity is dominated by Li+ ions and the presence of MnO2 has negligible effect. The ac conductivity data has been analysed by filing the data into Almond-West type power law behaviour sigma = sigma(o)+A omega(s). The power law exponent s is also determined and it is found to decrease with increase of temperature. We have also carried out the scaling behaviour of the ac conductivity and it is seen that all the curves coalesce on to a master curve suggesting that the ion transport mechanism remains unaffected at all temperatures. The results are discussed in the light of the structure of borate glass network. (c) 2005 Elsevier B.V. All rights reserved.