Study on the high-precision measurement method of electrical resistivity in pure iron with small sample size

The magnitude of the input current influences the measurement of electrical resistivity, and specifically, using a 100 mA input current results in significantly fewer measurement errors than using a 10 mA input current. The repeatability and the accuracy of the electrical resistivity measured in single-current mode are higher than those in dual-current mode.The effect of the sample size on the measurement values of the electrical resistivity is remarkable: the smaller the sample’s width and thickness, the higher the measurement accuracy of the electrical resistivity values.In the same case, the size effect in the thickness direction is more pronounced than that in the width direction.The resistivity measurement errors resulting from the above single or dual-current mode, input current, and size effect can be attributed to more severe dispersion or distortion of the electrical field in the surface layer of the samples during the four-probe measurement.