I am studying on Fe powder samples.
I have used I-V measurement system to get resistivty.
However, I would like to measure with 4-point probe.
but I am confused how to prepare the powder sample for 4-point probe.
could you tell me there is a way?
recently, I did a experiment about insulating coating on a powder.
and I measured resistance with various voltage.
according to Ohm's law, the resistance is constant
however, my sample showed different resistance with difference V.
At every voltage, I checked the currents and the resistance...