i have analyze impedance spectrum of my sample using z-view software. i found that at higher frequency one semi circle is fitted correspond to grain effect and at lower frequency another semi circle is there which correspond to grain boundary resistance. so from z-view software i got omega maximum for both grain and grain boundary, but when i convert it into relaxation frequency using relation fmax = omega max/2pie than i found that the grain relaxation frequency have smaller value compared to grain boundary relaxation frequency. so this kind of behavior is possible or not?
It is very possible. We have shown (doi:10.1016/j.jseaes.2015.04.016) that the electrical conductivity of gabbro (and most other igneous and high-grade metamorphic rocks) is dominated by positive hole charge carriers that derive from peroxy defects. A fair portion of these defects line or even straddle grain boundaries, where they are particularly sensitive to activation by stress. It is likely that, therefore, the charge carrier density along grain boundaries is distinctly higher than that inside grains, allowing for different, presumably higher frequencies
Dear Dr. Joshi and Dr. Nobre,
very stimulating discussion. I would be interested in collaborating with someone who can do impedance spectroscopy on rock samples over the temperature range from ambient to about 500-600°C, preferentially (but not necessarily) under protective inert gas atmosphere. We have a great deal of supporting data but are lacking impedance.
Thanks
Friedemann
Thank you very much Dr. Friedemann and Dr. Marcos for valuable suggestion
Dear Dr. Nobre and Dr. Joshi,
thanks for the interest. We should discuss the possibilities
Friedemann
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