Contactless technique for the measurement of electrical resistivity in anisotropic materials

Measurement of basal plane electrical resistivities in quasi-two-dimensional materials by conventional four-point bridge techniques is extremely difficult. In making measurements of room temperature basal plane resistivities in highly conducting highly anisotropic synthetic metals we have developed an rf inductive technique which is both simple to use and provides accurate results. At the frequency we employ (100 kHz) the method is appropriate for resistivities in the range 10 (-3)-10(-7)Omega cm. Samples are thin square plates 5 mm on a side. The system is calibrated by fitting data from a series of samples of known resistivity to semi-empirical formulae. The theoretical motivation leading to these expressions is discussed and extensive calibration data are presented. The advantages of rf techniques in general have already been discussed. Two advantages commend the particular technique we describe here. First, it is simple in design and easily constructed. Second, with careful calibration, highly accurate resistivity measurements can be made in a very straightforward manner.