A device is described that enables rapid measurements of the specific resistivity of powdered semiconductors and metals. The apparatus is especially useful for the screening of a large number of materials as the only sample preparation involved is the pressing of a pellet of the material. The 4hyphen;probe van der Pauw method with pressure contacts is used. Circuits for both ac and dc measurements are given and their relative merits discussed. The cell can be used between 77 and 400 K. A controlled atmosphere can be maintained around the sample.
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