I have done the dielectric measurement of conducting polymer nanocomposites containing some metal sulphide as nanofiller. And its d.c conductivity was in the range of 5-100 S/cm. when I measured the imaginary and real part of dielectric constant using LCR instruments in the range of 100 Hz-1 MHz, it is observed that the dc conductivity and dielectric parameters followed the same order and we got dielectric loss and constant value in the order of thousands. such high values are already reported for some polyaniline nanocomposites.My doubt is how a conducting material can be dielectric at the same time.
WHAT IS THE RELATIONSHIP BETWEEN D.C CONDUCTIVITY AND A.C. CONDUCTIVITY?
Hi Femina, we have come across similar behavior in our lab with some composite films. It seems the best explanation of the behavior is that there is significant trapping in the material. Under DC conditions the traps are able to fill then allowing charge transfer via hopping between what are now very shallow traps. Under AC conditions, the traps are never able to fill to the same level (as under AC conditions there is no net flow of charge in the material - just "back and forth") so charge remains isolated within them. It would be interesting to try running your AC measurements after a prolonged DC exposure and see how they then behave, and see if you could observe any relaxation from the DC conduction state over time.
This subject has been discussed multiple times in Researchgate. The electrical conductivity has direct relationship with the measurement frequency, dielectric constant and dissipation factor as follows.
σ = ω εoε' tan δ
Thank you, sir, for your response @ Hatsuo Ishida
I have reviewed all those discussions, but my case appeared to be a little confusing as the composite shows significant conductivity and dielectric permittivity
- Badges
- Science topic
- Similar topics
- Instrumentation Engineering
- Instruments