Abstract

Results on the giant magnetoimpedance (GMI) effect measured at 10 MHz and 500 MHz in an array of microwires containing a number of thin Co59.2Fe4.8Ni11B14Si11 amorphous glass-coated microwires are presented. The GMI effect was measured as a function of the number, n, of microwires from 1 till 30 involved in the array. The shape of the GMI field dependence at 10 MHz of a single microwire is typical for the materials with circular magnetic anisotropy, exhibiting a maximum at certain dc axial magnetic field H-max. At 10 MHz the GMI ratio of thin microwires array decreases as increasing the number n of microwires of the array. On the other hand, at 500 MHz H-m(n) has an opposite dependence, decreasing with n. The observed phenomena can be understand taking into account the magnetostatic interaction between the microwires placed closely in the array and also as a partial shielding of the applied magnetic field by the microwires. A remarkable difference in the frequency dependence of the GMI effect can be attributed to the frequency dependence of the shielding related with the frequency dependence of the magnetic permeability.