The influence of longitudinal field annealing on the giant magnetoimpedance (GMI) effect in Co70Fe5Si15Nb2.2Cu0.8B7 amorphous ribbons has been investigated. It was found that annealing in the open air at magnetic fields smaller than the anisotropy field along the ribbon gave rise to the GMI-valve phenomenon, while annealing at magnetic fields higher than the anisotropy field significantly reduced the GMI effect. The GMI-valve behavior corresponding to the highest field sensitivity of GMI (125%/Oe) was observed at a frequency of 0.1 MHz in the ribbon annealed under an applied field of 2 Oe. This is ideal for developing sensitive and quick-response magnetic sensors. The GMI-valve behavior observed in the Co-based amorphous ribbon due to field annealing can be explained by considering the complex permeability spectra in relation to the rotational dc magnetization.
|Translated title of the contribution||Valve behavior of the giant magneto-impedance in field-annealed Co70Fe5Si15Nb2.2Cu0.8B7 amorphous ribbon|
|Pages (from-to)||10M108-1 - 10M108-3|
|Number of pages||3|
|Journal||Journal of Applied Physics|
|Publication status||Published - May 2005|