Off-diagonal magnetoimpedance in amorphous wires and its application in miniature sensors of weak magnetic fields

Abstract

Off-diagonal magnetoimpedance in amorphous cobalt-based microwire with helical magnetic anisotropy is investigated using a DC bias current. It is demonstrated that the circular magnetic field generated by the bias current improves the sensitivity to an axial external magnetic field, raises the output voltage peak, and expands the sensed field in which the peak is observed. However, a further increase in the bias current reduces the sensitivity. The experimental results agree qualitatively with the theory for large bias fields when the hysteresis in static magnetization is eliminated.