Nonlinear Magnetoimpedance Effect in FeCoNi Ferromagnetic Tubes

The very high (up to 820% of the magnetoimpedance ratio) and sensitive nonlinear giant magnetoimpedance effect has been studied in the FeCoNi magnetic tubes electroplated onto Cu(3%)Be nonmagnetic wire for frequencies from 1 to 10MHz. Special annealing was done in order to induce the magnetic anisotropy. The high harmonic generation was observed and the harmonics show larger variations with the external magnetic field than the fundamental frequency. The super high sensitivity of the harmonics is promising in regards for the increase of the sensitivity of magnetoimpedance sensors.