When an external magnetic field is applied, the size of the permeability diminishes, increasing the penetration of the current in the magnetic material. Large variations are observed in both in-phase and out-of-phase components of the magnetoimpedance for applied magnetic fields close to the value of the Earth magnetic field up to few tens of Oersted. For comparison, in normal electrical conductors the effect of the skin-depth becomes important for frequencies in the microwave range only.