Stress and field contactless sensor based on the scattering of electromagnetic waves by a single ferromagnetic microwire

In this paper, we report an experimental study on the microwave modulated scattering intensity for a single Fe_2.25Co_72.75Si_10B_15 amorphous metallic microwire. The modulation is driven by applying a bias magnetic field that tunes the magnetic permeability of the ferromagnetic microwire. Furthermore, by using a magnetostrictive microwire, we also demonstrate that the microwave scattering is sensitive to mechanical stresses. In fact, we present a wireless microwave controlled stress sensor, suitable for biological applications, as a possible use of this effect. In addition, a first order theoretical approximation accounts for the observed influence of the magnetic permeability on the scattering coefficients. That model leads to predictions in good agreement with the experimental results