Linear impedance of 50(2Bi2O3-V2O5)-50SrB4O7 glass heat treated two times measured with impedance spectroscopy method at low temperatures

The linear electrcial properties of 50(2Bi2O3-V2O5)-50SrB4O7 glass heat treated two times was measured by impedance spectroscopy method. 
 The polycrystalline strontium–borate, SrB4O7 was synthesized via a solid state reaction route that involved heating stoichiometric mixtures of analytical grade SrCO3 and H3BO3 at 1073 K for 12 hours. Next, sample of a composition of 50(2Bi2O3-V2O5)-50SrB4O7 (in %mol) was prepared from reagent-grade Bi2O3, V2O5 and preprepared SrB4O7. Samples of glass were prepared by the conventional melt quenching technique. The melting was conducted in alumina crucibles at 1373 K for 2 hours. The melt was poured onto a preheated (573 K) brass plate and pressed by another plate to obtain flat circular disks of 1–2 mm thickness and 20–30 mm in diameter. Glass samples were heat treated two times at 693 K and next at 813 K to obtain fully crystallized samples.
 For the electrical measurements gold electrodes were evaporated at the preheated samples. Impedance measurements were carried out in the frequency range from 1 mHz to 1 MHz and the temperature range from 153 K to 423 K, with the ac voltage of 1Vrms with Concept 40 broadband dielectric spectrometer.