Balancing the contact potential difference in measurements of the electrical resistance of metals and alloys

摘要

The measurement of electrical resistance provides a convenient route to studying changes in the atomic and magnetic structure of metals and alloys, phase transformations, etc., and is thus a simple technique for monitoring the structural conditions of materials [1]. Low- and middle-value resistances are reliably measured by the four-probe voltammetric method [1]. The voltage measured by a voltmeter includes the voltage drop across the potential probes through which the current is passing and the contact potential difference (CPD). The standard technique for balancing CPD effects involves measurement of the forward and reverse currents. This technique, widely used in practice, employs point-by-point measurements and requires some amount of computational work. When used for measurements in a continuous mode, this method encounters problems, mainly associated with the data processing and the commutation of high-precision instruments, which is frequently an inconvenience.