Stress-Driven Magnetic Barkhausen Noise Generation in FeCo Magnetostrictive Alloy

Abstract

Stress-driven magnetic Barkhausen noise (MBN) can be potentially used to develop a high-sensitivity dynamic force sensor. MBN is a compositional pulse due to the domain wall movement in ferromagnetic material induced by the external field. In this study, we provide an in-depth understanding of the responsiveness of MBN to external stress using ferromagnetic materials with a high magnetostriction constant ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> ). We demonstrate stress-driven MBN from strong textured Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">29</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">71</sub> alloy wires ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{\mathrm {s}} =117$ </tex-math></inline-formula> ppm)/epoxy resin composite via uniaxial compression testing by changing the stress rate level from 0.55 to 28 GPa/s under a static bias magnetic field of 55 mT. The relationship between the stress rate of the external force and root-mean-square (rms) value of MBN output voltages showed high sensitivity, i.e., <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm {rms}}= 0.00441 (d\sigma /dt)$ </tex-math></inline-formula> , and acceptable linearity that could be used to quantitatively evaluate the dynamic force. This stress-driven MBN generation mechanism could be based on the domain wall movement induced by the inverse magnetostrictive effect of FeCo alloys. We believe that this study will aid in the research focusing on the dynamic magnetostrictive mechanism and development of novel applications for high-sensitivity force sensors that have no batteries.