Ultrasonic characterisation of ferroelectric BaTiO3 doped lead bismuth oxide semiconducting glasses

Ferroelectric BaTiO3 doped lead bismuth xPbO-(100 - x)Bi2O3-5BaTiO(3) semic onducting oxide glasses with different PbO contents (x = 20, 30, 40 and 50 wt%) have been prepared by the rapid quenching method. The ultrasonic veloc ity and attenuation measurements have been made at room temperature (298 K) at frequencies 2.25-10 MHz. From the measured density and ultrasonic veloc ity data, elastic moduli, Debye temperature, Poisson's ratio and other rela ted physical parameters have been determined. At lower PbO content (PbO < 4 0 wt%), a monotonic decrease in velocity, elastic moduli and Debye temperat ure was noted. A further increase in PbO content (PbO > 40 wt %) lead to an increase in all the above parameters, after showing a minimum at 40 wt% of PbO. In addition, the effect of ultrasonic frequency on velocity and atten uation has also been studied in these glasses. The observed results have be en explained in terms of the change in the structure and physical propertie s of the glass network with change in PbO content. (C) 2001 Elsevier Scienc e B.V. All rights reserved.