In a four probe method, if the area between the two probes is constant, then will the resistance change with the sample size?
Your question is not completely clear. In the four pin method of measuring resistivity, the volume of the sample that is being measured is determined by the distance between the middle two probes. If that distance is constant, then the volume of electrolyte that is being measured remains the same. The resistivity measured must therefore remain the same unless the properties of the electrolyte are changed between measurements.
Thanks Smith.
I was measuring this IV by four probe on the thin films. Therefore, as you said if the distance between the middle two probes is constant in all measurements, in that case, will the resistivity will be dependent on size of sample?
Since you are making your measurements on a thin film, the measured resistance will vary with the thickness up to the point where the thickness equals the distance between the two measurement pins. If you would like to learn about the math behind the measurements, google "four pin Wenner method" to see how this is done in soils where the sample thickness is essentially infinite.
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