Characterization of Electric and Magnetic Material Properties with Eddy-Current Measurements

Abstract The electrical conductivity σ and the magnetic permeability μ are the basic material properties that describe the interaction between an eddy-current sensor and a sample, They are connected strongly to technologically relevant quantities and thus have to be determined for a complete characterization of the material. This work presents a method to evaluate conductivity and permeability by eddy-current measurements. Since appropriate calibration samples are not available, the necessary calibration procedure is performed by simulation of the measurement. The nonlinear magnetic effects, which are small but not completely avoidable. afford an approximation that leads to the definition of an effective permeability μeff. The comparison of the eddy-current results with reference values, which are obtained by other techniques, reveals a deviation less than 9% in σ and less than 14% in μeff.