Giant magneto-impedance effects in nanocrystalline soft magnetic alloy ribbons

摘要

SINCE the discovery of the giant magneto-impedance (GMI) effects in amorphous wire (or ribbon) of CoFeSiB and nanocrystalline wire (or film) of FeCuNbSiB, it has attracted great attention due to its promising potential applications in industry. Amorphous (and nanocrystalline) soft magnetic alloys have very large magnetic permeability, when an ac driving current and an external magnetic field (EMF) are applied, the EMF will damp the magnetic flux change caused by the ac driving current, thus the magnetic permeability will decrease; as a result, the penetration depth will increase, hence the impedance, Z=R+jX, of the specimen will decrease, finally resulting in GMI (R, X, Z) effects.