I'm working on dielectric properties of bulk ferrites. The plots of dielectric constant with frequency and dielectric loss show Maxwell-Wagner behavior. FESEM images show there are grain and grain boundaries. But if I convert the data into impedance and Nyquist plots, they show only one semicircle (in few samples) and one semicircle with line (in few samples). The both results from FESEM and impedance data were not matching. Why? Could anyone please help me out.
It is not mysterious, if you don't get two distinct semicircles for grain core and grain boundary for some samples. There could be predominantly two reasons.
1. If the resistivity of the grains and grain boundaries are close for a sample, then the associated semicircles can merge to create a single depressed semicircle.
2. The two semicircles are found one at the low frequency end, and the other at the high frequency end. If in some case one of the semicircles shift out of the operating frequency range for some reason, it might not get detected. The shifting may depend on the electrical inertia and nature of the associated oscillators.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science