Giant magnetoimpedance effect in Fe79.5P12C6Mo0.5Cu0.5Si1.5 nanocrystalline ribbons

Nanocrystalline structure was observed in Fe79.5P12C6Mo0.5Cu0.5Si1.5 ribbons after annealed at temperatures from 350 to 500°C. After annealed at 350°C, the ribbon Fe79.5P12C6Mo0.5Cu0.5Si1.5 consists of nanoparticles bcc α-Fe(Si, C) and amorphous matrix. Nanoparticles α-Fe(Si, C) and Fe3P appear in Fe79.5P12C6Mo0.5Cu0.5Si1.5 ribbon after annealed at 500°C. The giant magnetoimpedance effect was found in nanocrystalline Fe79.5P12C6Mo0.5Cu0.5Si1.5 ribbons. In the frequency range of 0.1–10 MHz, there is a maximum of magnetoimpedance ratio at 6.9, 1.9, and 1.5 MHz for samples with annealing temperatures of 350, 400, and 450°C, respectively. The value of (Z(0)-Z(65Oe))/Z(0) for the nanocrystalline ribbon Fe79.5P12C6Mo0.5Cu0.5Si1.5 with annealing temperature 450°C can reach the value of 13% at 1.5 MHz. The GMI effect in Fe79.5P12C6Mo0.5Cu0.5Si1.5 ribbon annealed at 500°C is very small (less than 2%).