Micro-macro characteristics between domain wall motion and magnetic Barkhausen noise under tensile stress

Abstract

One challenge of stress measurement by using Magnetic Barkhausen noise (MBN) is to build correlation model between MBN and micro magnetic characterization of the material. In particular, it highly requires a quantitative evaluation for micro-macro magnetic properties characterizing under the stress impaction. In this study, a correlation model between domain wall (DW) motion and MBN under tensile stress is established and promoted. Optical flow (OF) traces motion of magnetic domain images, which can quantify the status of DW motion during magnetization process. When applied field is in stress direction, tensile stress aligns the magnetic domains parallel to the stress direction and makes coercive field decrease. This can make a phenomenon vary of DW motion as well as MBN signal. The average velocity of DW motion (OF value) is proportional to MBN signal under tensile stress. Root mean square (RMS) and mean value are extracted from both DW motion velocity (OF value) and MBN signal to quantitatively analyze the changes under tensile stress to quantify the correlation between micro and macro magnetic parameters. In addition, the correlation model between DW motion and MBN is quantitatively analyzed in different locations to evaluate the repeatability of the correlation, as well as the effect of microstructure on MBN and DW motion under the tensile stress. The correlation coefficient of RMS and mean value show the highly correlation between DW motion and MBN, which in turn sheds deep understanding the micro-macro property-physic mechanisms. The proposed work has potential for interpretation of the statistical properties of MBN under different tensile stress by studying DW motion, which can be further applied for enhancing accuracy on stress measurement.