Giant magnetoimpedance effect in surface modified CoFeMoSiB amorphous ribbons

Thin magnetic Fe layers in thickness of 10-240 nm were deposited onto a wheel surface of CoFeMoSiB amorphous ribbons to check our concept of a new type of heterogeneous magnetoimpedance materials formed by two different magnetic parts. The presence of an additional iron layer modifies the magnetoimpedance response of the composite material and leads to increase of the magnetoimpedance ratio from 330 to 345% at a frequency of 3.5 MHz. Two possible mechanisms are discussed for explanation to the observed behaviour. Modification of the surface properties of the amorphous ribbons may have certain potential for technological applications.