I have done high temperature impedance measurement for my pellets using 2 methods.
1. Using Platinum mesh alone on both sides of sintered pellet.
2. Pt paste was brushed on both sides of pellet and then mesh was placed
Why there is variation even in grain and grain boundary resistance values?
which method provides good result..Can measurement can be done without platinum paste?
Thank You sir. I baked the sample at 750C only. The additional curve is due to baking the sample at low temperature?But however how the contact has an influence on the grain resistance of the sample ? It has to be reflected on the low frequency semicircle part ?
you measure your 1)pellet in series with your 2)electrical contact. In order to avoid case 2, i.e. to measure your pellet (electrical properties, only!), then :
we propose Pt paste (4 point electrical contacts) on ONE side of your pellet (van der Pauw method; for more see refs 1,2)
1. https://en.wikipedia.org/wiki/Van_der_Pauw_method
2. http://astro1.panet.utoledo.edu/~relling2/teach/6180-7180/Hall_effect_van%20der%20Pauw_1958.pdf
Pt paste on sides of pellet is a good method to to impedance spectroscopy as it equally distribute the charges deeper into the sample...........
As Mr. Braun has said, method 2 is mostly used in ac impedance spectroscopy. We also use the same. Pt paste is brushed on both sides of pellet and is placed in between Pt mesh. However, we bake the samples at 900 C for 1 hr.
Hi Preethi,
you measure a two-fold electrical contact. As Artur said : "..., here you create an additional interface which shows up in the impedance spectrum.". So the additional RC2 is due to the additional (electrical contact) interface. If you know that (two-fold contact) activity, having a LOW-ZRC2 contribution, then you may focus to the rest of Z-spectra e.g. studying the pellets' (material) properties activity.
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