When I draw cole-cole plot of impedance for all temperatures then the center of the semicircles looks below real axis but for an individual temperature plot the semicircle shows the center above real axis. Then from which graph we can decide the centre of semicircle? I here attach a plot of cole-cole.
If you have temperature dependet data you may try to use first the time-temperature supreposition principle (here frequency - temperature superposition principle) to make a so-called master curve by shifting the temperature dependent data horizontally and the plot this master curev in the Cole-Cole form. It seems, however, that in your case the limiting values are also frequency dependent. You may have more relaxation mechanisms in the wide temperature range you are using and switch between them. Please plot the freqency dependent data at various temperatures. By the way if you plot the impedances it is rather a Nyquist plot, not a Cole-Cole diagram.
In a Cole-Cole plot a Debye peak appears as a semicircumference centered in ( eps_inf +Delta_eps/2 ,0) and diameter Delta_eps. Deviations from the perfect circular shape indicate deviations from the Debye type. In general, in the case of an Havriliak-Negami (HN) relaxation function, in a Cole Cole plot you'd obtain an arc, cutting the x-axis in eps_inf and eps_inf + Delta_eps, and intersecting it with angles 1/2 pi alpha beta and 1/2 pi alpha beta, where alpha and beta are respectively the symmetric and the asymmetric shape parameters of the HN function. If the two angles are similar (= 1/2 pi alpha) then you have a Cole-Cole function. Anyway, I'd recommend using a regular fit in the frequency domain with an HN function, rather than using the obsolete Cole-Cole representation.
If you have temperature dependet data you may try to use first the time-temperature supreposition principle (here frequency - temperature superposition principle) to make a so-called master curve by shifting the temperature dependent data horizontally and the plot this master curev in the Cole-Cole form. It seems, however, that in your case the limiting values are also frequency dependent. You may have more relaxation mechanisms in the wide temperature range you are using and switch between them. Please plot the freqency dependent data at various temperatures. By the way if you plot the impedances it is rather a Nyquist plot, not a Cole-Cole diagram.
Hi,
Cole-Cole plots are Argand Plots, drawn for a complex quantities.
It means, you should take similar scales on both axes. In doing so you get similar plot whether you plot for all temperatures or for individual temperatures. Hope this will help you.
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