Multilayered magneto-impedance microsensors for non destructive control

Magnetic field microsensors based on the magneto-impedance phenomenon have been fabricated by stacking up ferromagnetic/conductive/ferromagnetic films. Their sensitivity is in the same range than macroscopic devices (i.e. 400 V/T/A) and is constant from 0 to 500 A m
^-1
. The ferromagnetic layer is a Finemet® alloy. Initially an amorphous material, it is nanocrystallized by heat treatment. Its magnetic properties have been optimized in order to induce transversal anisotropy.