Existence of Three Stable States of Magnetic Domain for the Stepped Giant Magnetoimpedance Element and Proposal for Sensor With Memory Function

In this paper, a giant magnetoimpedance (GMI) element with stepped impedance property was reported for rectangular amorphous soft magnetic thin film with an in-plane uniaxial easy axis in a controlled direction. This stepped change of impedance occurs simultaneously with a change in a magnetic domain, and its physical basis was explained as the intersection of the level of magnetic energy in each case of these domain structures. The variation of stepped impedance as a function of external magnetic field typically has a hysteretic property. The hysteretic property is explained based on an existence of threshold energy barrier which is needed overcoming to change the magnetic domain. In this paper, we will show experimentally both an existence of three stable magnetic domains around zero external magnetic field by using the stepped GMI element, and a possibility to detect these states by impedance measurement. We also propose an application of this phenomenon for a magnetic sensor which has a memory function.