بحث
Ferroelectricity of the glassy material Bi-Pb-Cu-O doped with K ions

A.A. Bahgat1, B.A.A. Makram1, E.E. Shaisha1 and M.M. El-Desoky2
 

Abstract

 

Glass sample of the composition 31.4 Bi2O3 – 2.33 Pb3O4 – 64.53 CuO – 1.74 K2O in mol% was prepared by the conventional quenching melt technique. The as quenched single phase glass shows interesting ferroelectric properties which is not familiar in the field of glass science. If the as quenched glass is heat treated at or above the glass transition temperature all signs of ferroelectricity disappears completely. X-ray diffraction and transmission electron microscopy as well as differential thermal analysis were used to recognize the glassy nature of the as quenched sample. Ac dielectric measurements were performed at different applied frequencies as a function of temperature. On the other hand the dc electrical conductivity of the present glass can be fitted with Mott's model of nearest neighbor hopping at high temperature, while at intermediate temperature the Greaves VRH (variable-range hopping) model was found to be appropriate. The conduction was confirmed to obey the adiabatic small polaron hopping (SPH) and was mainly due to electronic transport between Cu ions. The dominant factor determining conductivity was the hopping carrier mobility in this glass.  From the best fits, reasonable values of various SPH and VRH parameters are obtained.






شارك برايك
مارايك في موقعنا الجديد