Magnetic domain observation of stepped giant magneto-impedance sensor with subjecting to normal magnetic field

A thin film giant magneto-impedance (GMI) sensor has a unique property of step-like magneto-impedance change, in case the sensor has in-plane uniaxial inclined easy axis. A domain observation shows that the step-like change is due to magnetization transition within three states, such as longitudinal single domain with parallel, the one with anti-parallel and inclined Landau-Lifshitz domain (ILLD). In a condition where the sensor has easy axis of 70 degrees relative to short side axis of the element, the transition is limited between the parallel and anti-parallel in spite of existing of stable ILLD [6]. The previous work showed that an application of normal field has possibility of making the ILLD state arise [7], In this study, an observation of magnetic domain using Kerr microscope when the sensor is subjecting to a normal field is reported. An existence of distributed canted angle relative to normal direction within the applied field enhances the reconstruction of ILLD domain state.