Property and Magnetic Domain of Thin Film MI Sensor with Subjecting to Normal Magnetic Field

Abstract

A thin-film magnetic field sensor is useful for detecting foreign matters and nanoparticles included in industrial and medical products. It can detect a small piece of tool steel chipping or breakage inside the products nondestructively. An inspection of all items in the manufacturing process is desirable for the smart manufacturing system. A previous study proposed a sensing system in which a thin-film magneto-impedance sensor was set in a strong normal magnetic field and detected the foreign matters at the same time as magnetization. In this paper, an impedance property of a thin-film magneto-impedance sensor and magnetic domain of it is investigated within up to 0.35 T normal magnetic fields against substrate plane for the purpose of improving performances of the proposed sensing system. A verification of sensitivity of the sensor was also carried out subjecting to 0.3 T normal magnetic fields.