Analysis of Resistivity Measurements by the Eddy Current Decay Method

Abstract

A systematic analysis is presented of the conditions in which the measurements of resistivities of metallic samples by the eddy current decay method give meaningful and accurate results. Coil sample geometry and material parameters are examined by means of equivalent circuits, and ways of extracting the desired information from the signal are discussed. We report selected measurements on critical parameters. A carefully designed and tested apparatus for the accurate determination of resistivity at room and helium temperatures with an operational logarithmic amplifier has been constructed. Most of the important conclusions of this study are displayed in graphical form to assist workers in the field.