Frequency dependence of the magnetoimpedance in nanocrystalline FeCuNbSiB with high transverse stress-induced magnetic anisotropy

Stress-annealed nanocrystalline FeCuNbSiB ribbons show correlation between induced magnetic anisotropy and magnetoimpedance. Two types of crystallization process were used in order to induce a transverse magnetic anisotropy: the first one was performed submitting the original amorphous samples to an applied tensile stress of /spl sigma/=150 MPa. In the second one, samples are nanocrystallised in a first stage and submitted to stress annealing at /spl sigma/=290 MPa afterwards. The maximum of the magnetoimpedance can be obtained for dc fields larger than the anisotropy field of the sample or close to the irreversibility field. This behavior can be explained based in the simultaneous switching of two different magnetization processes taking place in the samples with high transverse magnetic anisotropy.