Preparation and characterization of Bi2O3-PbO-R (R=Fe2O3, MnO2, CuO and V2O5) semiconducting oxide glasses

A series of Bi 2 O 3 -PbO-R (R=Fe 2 O 3 , MnO 2 , CuO and V 2 O 5 ) glasses have been prepared from the respective melts to room temperature by rapidly quenching between two highly polished copper blocks. Bi 2 O 3 was kept fixed (40 mol%) for all the glasses. The remaining 60 mol% was varied between PbO and R. PbO was kept between 59.9 to 50.0 mol% whereas R was varied between 0.1 to 10.0 mol%. Dc conductivity of all the glasses was measured at the temperature range (400-700K). The conductivity was found due to small polaron hopping conduction in the non-adiabatic region. At 650K, the conductivity of lmol% R was found to be maximum (∼10 -7 ohm -1 cm -1 ) for R=MnO 2 and minimum (∼10 -9 ohm -1 cm -1 ) for R=Fe 2 O 3 . The 'g' values calculated from Electron Paramagnetic Resonance (EPR) signal varies from sample to sample. For all the samples one of 'g' values obtained nearly 2.0 whereas for R=Fe 2 O 3 sample 'g' values of 4.3, 7.4 are also observed.