I have some (carbonaceous material) samples which are in the shape of slabs with uniform thickness. What formula should I use to measure it's conductivity if I am using four probe method?
You can calculate from slope of I-V curve.
It depends what type of configuration for measurement you have. If you want to normalize it you may need length and width(there is trend of normalizing conductivity in 2D system).
If the shape of your samples is irregular, you may use Van der Pauw method. Or do you use rectangular shapes ? If the latter applies, then indeed you just have to fix a given (low) current and measure the voltage drop. Then apply Om's law. You should also invert the sense of the current and measure the new voltage. You'll find a small difference due to thermoelectric power of the material. For correcting it, just do the average of the resistance measured with the current flowing in one direction, then in the opposite direction. The measurements should also e=be carried out at controlled constant temperature.
Alain
There is a formula , especially to find conductivity for samples like nanofiber mat , thin films using four probe method : ρ(o) [ resistivity ] = 2*pi*S*(V/I) , where S is the distance between the probes which is a constant - 0.2 cm and (V/I) should be obtained form the instruments . Also , if the sample thickness is less than the distance between the probes [ i.e thickness
you can have a detailed study on this method in book and link given below.
Semiconductor Material and Device Characterization by Dieter K. Schroder...
http://books.google.co.in/books/about/Semiconductor_Material_and_Device_Charac.html?id=OX2cHKJWCKgC
how can I measure the conductivity from the I V plots? I don't have any other data
Dear Vikram S Raghavan,
Thanks for your answer, could you please give the detailed formula for correction factor, if any reference would be better.
May I Know How to measure the conductivity of a PANI pellet of diameter of 10mm.
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