Mm. Elkholy et Ma. Elshahawy, FREQUENCY AND TEMPERATURE DEPENDENCIES OF AC CONDUCTIVITY OF POLYVINYL-ALCOHOL (PVA)-COCL2 COMPOSITES, Journal of materials science. Materials in electronics, 4(4), 1993, pp. 278-282
The a.c. conductivity for polyvinyl alcohol (PVA)-CoCl2 composites pre
pared by a casting method has been measured at different frequencies (
0.1 -1 0 kHz) in the temperature range 300-450 K. At constant temperat
ure, the frequency dependence of a.c. conductivity, sigma(omega), was
found to fit the established equation sigma(omega) = Aomega(S) quite w
ell. On the other hand, the temperature dependence of a.c. conductivit
y suggested an electronic hopping conduction mechanism in a thermally
assisted electric field. Various theoretical mechanisms have been disc
ussed to clarify the conduction processes in these samples. The correl
ated barrier hopping (CBH) mechanism, proposed by Elliott, was found t
o be the most appropriate one.