Giant magnetoimpedance sensor integrated in an oscillator system

This article presents a magnetic field measurement system using giant magnetoimpedance (GMI) sensor as a phase shift element. Investigations were carried out using CoFeB trilayer thin films with 2kA∕m anisotropy field structured as strips and meanders of 300μm length presented in previous studies. The GMI sensor is integrated into an oscillator circuit. The measurement system detects the phase change caused by the magnetic field to be measured. A 6.85% impedance decrease at an applied field of 1.4mT was observed. The phase difference in such cases was Δφ=1.12°. The transmission constant was μa∕Δφ=1mV∕deg.