  A remarkably strong dependence of magnetoimpedance (MI) on tensile stress has
been observed in the microwave frequency range for thin CoMnSiB glass-coated
microwires exposed to a special thermal treatment. The MI ratio runs into more
than 100% at 0.5-1.5 GHz when the tensile stress of 600 MPa is applied to the
wire. It was demonstrated that a large MI change at such high frequencies is
related predominantly with the dc magnetization orientation. A host of such
microwires incorporated into a dielectric matrix may constitute a new sensing
medium that is characterized by the stress-dependent effective permittivity.
Such medium can be used for the microwave visualization of the stress
distribution inside of a composite structure or on its surface.
