TY - CONF A1 - Pelkner, Matthias A1 - Erthner, Thomas A1 - Reimund, Verena A1 - Kreutzbruck, Marc A1 - Sergeeva-Chollet, N. T1 - MR-based eddy current probe design for hidden defects T2 - ECNDT 2014 - 11th European conference on non-destructive testing (Proceedings) N2 - We present a simulation study which pursues the objective to find probe geometries for a MR-based eddy current (EC) probe (MR magneto resistance, e.g., GMR giant magneto resistance, TMR tunnel magneto resistance). MR sensor technology exhibits two significant advantages compared with conventional coil systems. First, MR sensors are relatively frequency-independent within common EC-frequency ranges which enable us to operate them in hidden defects testing problems. Secondly, MR technology is well suited for miniaturization helping us to design small elements in the order of below 100 µm. In this paper simulation and experimental results obtained with the probes for low frequency application, i.e. for hidden defects detection are discussed. Our simulations are based on two different approaches for a better validation, a commercial finite element method software (Opera, Vectorfields) and the semi-analytical software CIVA. We investigated both coil arrangement in order to excite sufficient high eddy currents inside the test samples and position of MR-elements at the array chip. In doing so the MR sensors were positioned that they are not exposed to excitation fields. In addition, different coil geometries, in particular coil length, e.g. Ι = 20 mm, were analyzed in order to generate a consistent eddy current distribution beneath an array of up to 32 MR-elements. To prove obtained probe principles we built GMR-EC-probes. The first test measurements are in good agreement with the simulations performed by BAM and CEA. On basis of our findings the IMAGIC consortium developed new MR-EC-probes using integrated ASIC technology. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 2014-10-06 KW - Magneto resistance (MR) KW - Eddy current (EC) KW - Simulation KW - GMR KW - Magnetic flux leakage KW - Hidden defects PY - 2014 UR - http://www.ndt.net/events/ECNDT2014/app/content/Paper/409_Pelkner.pdf SN - 978-80-214-5018-9 SP - 1 EP - 8(?) AN - OPUS4-32231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -