Abstract：The nanophase bcc α- Fe(Si) crystallizes from Fe72. 5Cu1Nb2V2Si13. 5B9 ribbon through thermal annealing. When the annealing temperature is higher than 550 ℃, the hardmagnetic phase Fe2B occurs accompanying with nanophase bcc α- Fe(Si). The nanocrystalline Fe72. 5Cu1Nb2V2Si13. 5B9 ribbons exhibit giant magnetoimpedance (GMI) effect, which sensitively depends on the annealing temperature. The optimal annealing temperature for obtaining stronger GMI is 550 ℃, where the average grain size of α- Fe(Si) is about 16 nm. The GMI effect also strongly depends upon the frequency. For Fe72. 5Cu1Nb2V2Si13. 5B9 nanocrystalline ribbon annealed at 550 ℃ for 30 min, ΔX/X under H=7162 A/m reaches -500% at 50 kHz,ΔR/R under H=7 162 A/m is -150％ at 3 MHz, and ΔZ/Z is -121％at 700 kHz.
2015, Vol. 22 
