Giant Magnetoimpedance in Fe_73.5Cu₁Nb₂V₁Si_13.5B₉Nanocrystalline Ribbons

Abstract

In the present work, the giant magnetoimpedance effect has been found in Fe73.5Cu1Nb2V1Si13.5B9 nanocrystalline ribbons. The optimum annealing temperature for obtaining largest GMI is about 550°C. Fe73.5Cu1Nb2V1Si13.5B9 with average grain size of 15 nm after annealing at 550°C for 30 min presents a magnetoimpedance of-74% at 700 kHz under H=90 Oe. The MI effect at high frequency is due to the change of Z via the variation of permeability or the penetration depth under the external field. The positive magnetoimpedance ΔZ/Z is 36% and positive magnetoresistance ΔR/R is 79% at H= 10 Oe and f=5MHz. We observe a huge magnetoreactance ΔX/X of –375% at a very low frequency of 50 kHz, which is a magnetoinduction effect due to the movement of domain wall. The smaller GMI for nanocrystalline Fe73.5Cu1Nb2V1Si13.5B9 ribbons annealed above 550°C is mainly connected with the decrease of permeability due to the precipitation of Fe2B phase in ribbons. Our results show that the partial substitution of expensive Nb by cheap V in FeCuNbSiB could be a successful way to prepare the GMI materials with high performance and low cost.