High-frequency magnetoimpedance properties in Finemet-type ribbons with a Cu-Co electrodeposited layer

The GMI vs applied field curve does not show a monotonic decay but displays a maximum. GMI first increases with frequencies up to ∼10 MHz reaching values of ΔZ/Zmax ∼ 20%. At higher frequencies the GMI ratio is seen to decrease becoming vanishingly small at ∼1 GHz.