Tailoring magnetic and microwave absorption properties of glass-coated soft ferromagnetic amorphous microwires for microwave energy sensing

A comparative study of the magnetic softness, giant magnetoimpedance (GMI) effect, and microwave absorption capacity of glass-coated amorphous Co_64.63Fe_4.97B₁₆Si₁₁Cr_3.4Ni_0.02 and Co₆₈B₁₅Si₁₀Mn₇ microwires has been performed. We find that the Mn-containing sample exhibits a softer magnetic property, a larger GMI ratio, and a higher microwave absorption capacity as compared to those with a Fe-Cr-Ni composition. As a result, the Mn-containing microwire is shown to be a better microwave absorber for fabrication of a new class of microwave energy sensor based on Fiber Bragg Grating. Our study emphasizes a correlation between the magnetic softness, GMI, and microwave absorption in the microwires and paves the way to improving the performance of such sensors by tailoring their soft magnetic properties.