“…Use of Hall probes for the pulsed eddy current application has been investigated by Bowler and Harrison[14], Johnson[15], and Waidelich[16], as well as others. Work has recently been reported on SQUIDs by Podney and Moulder[17]. A magnetoresistive sensor configuration has also been used in a fixed frequency eddy current measurement[18] to detect cracks.Although SQUIDs are the most sensitive of the listed magnetic sensors, their major drawback is that they must be cryogenically cooled and cannot operate near room temperature.…”