Defect evaluation using the phase information of an EC-GMR sensor

Phase information is employed to enhance evaluating defects in the metals by eddy current testing using the conventional probes. But for an EC-GMR sensor, the output phase is not used. In this paper, GMR-based eddy current defect detection is studied, in which the phase of the GMR sensor output is taken into account. Based on Biot-Savart law, amplitude and phase for the EC-GMR sensor's output are studied. This paper shows that defect can be better located through the phase analysis of the GMR sensor's output.