Current-controlled giant magnetoimpedance of iron single crystals

• Magnetoimpedance measurements on iron single crystals were performed in the low frequency regime.
• It is observed that there is a current threshold for inducing a giant magnetoimpedance effect.
• Calculations permit the determination of the effective circumferential permeability of the whiskers.
• It is found that the GMI effect has its origin in the circumferential magnetic domain structure of the specimen.

Extended magnetoimpedance measurements on iron single crystals(whiskers) with 〈100〉〈100〉 growth direction were performed at room temperature as a function of the applied longitudinal magnetic field and of the magnitude of the applied current in the low frequency regime. It is observed that there is a current threshold for inducing a giant magnetoimpedance effect. Calculations based on the standard skin effect formalism permit the determination of the effective circumferential permeability of the whiskers. It is found that the effect has its origin in the circumferential magnetic domain structure of the specimen. For comparison, impedance measurements on an iron wire were performed where no current threshold and continuous increase of the effective circumferential permeability is observed.