Influence of surface anisotropy on magnetoimpedance in wires

The variation of the amplitude of the giant magnetoimpedance maxima for a magnetic cylindrical conductor in the range of $\text{1<f<300\hspace{0.17em}}\mathrm{MHz}$ has been investigated. Emphasis is put on the effect of the surface anisotropy, $K_s,$ which was neglected in previous studies. The calculation of the impedance of a perfect anisotropic, nonsaturated wire with a helical magnetic structure also includes exchange-conductivity effects and Landau–Lifshitz damping. The results are compared with experimental data on CoFeSiB amorphous wires. It is found that other factors must also be taken into consideration to describe the data.