Ultra-large giant magnetoimpedance effect by a 2D square spiral amorphous microwire

Abstract

Giant magnetoimpedance (GMI) effect is suitable for application in magnetic field sensing technology due to its high sensitivity to magnetic field. Improving GMI effect through the optimization of some intrinsic properties such as component and domain structure of magnetic materials encounters great challenges. Inspired by the material-structure integrated design philosophy and metamaterial design paradigm, a joule-annealed Co68.7Fe4Si11B13Ni1Mo2.3 magnetic microwire with square spiral macrostructure is proposed here to tremendously enhance GMI ratio (∼43,000%) and magnetic field sensitivity (∼6300%/Oe), which smashes the restriction brought from the material itself on GMI effect intensity. The coupling effect of ferromagnetic resonance arising from intrinsic properties of the magnetic material itself and LC resonance induced by the inductance of the square spiral structure and the parasitic capacitance of the microstrip line proves to be responsible for the obtained ultra-large GMI effect. Moreover, considerable GMI performance can still be obtained above the ferromagnetic resonance frequency, broadening the operating frequency range and breaking the restriction caused by the single ferromagnetic resonance. These make the square spiral microwire an excellent candidate for sensing application. This work provides a new and comprehensive approach of material-structure integrated design with the superiority of symphony of material itself and macro-configuration to realize ultra-large GMI effect.