Characterization of ferromagnetic wires for self-sensing materials

Measuring ferromagnetic wires inside a metallic rectangular waveguide is proposed as a technique to characterize the high-frequency magnetoimpedance effect under mechanical stresses, which is of great interest for self-sensing materials in architectural and health monitoring. By using this technique, the magnetostrictive behaviour of a 5.25 μm radius Fe_77.5Si_12.5B₁₀ wire has been evaluated. The wire is characterized by the occurrence of the natural ferromagnetic resonance, whose frequency position is shifted from 7 GHz to 8.25 GHz for elongations ranging from 0 to 60 μm.