Giant magnetoimpedance in nanocrystalline Fe90.3−xZr7B2.7Cux (0.5 ≤ x ≤ 1.5) as-spun ribbons

The nanocrystalline ribbons Fe90.3−xZr7B2.7Cux with low Cu contents can be directly obtained through melt-spinning technique with an appropriate low quenching speed such as 22 m/s. Sizes of bcc-Fe grains precipitated in Fe90.3−xZr7B2.7Cux as-spun ribbons were 17 nm for x = 0.75, 15 nm for x = 1 and 12 nm for x = 1.25. The addition of Cu reduces grain size of bcc-Fe in as-spun nanocrystalline Fe90.3−xZr7B2.7Cux ribbons. Among the investigated samples (0.5 ≤ x ≤ 1.5), the largest magnetoimpedance can be obtained in the nanocrystalline Fe80.3Zr7B2.7Cu1 as-spun ribbon with x = 1. The value of magnetoimpedance (Z(H) − Z(0)) / Z(0) under H = 90 Oe for Fe80.3Zr7B2.7Cu1 as-spun ribbon reaches − 28.2% at a frequency of 1 MHz.