Asymmetric high-frequency carrier-type magnetic field sensor with thin-film head structure

An asymmetric giant magneto-impedance (GMI) sensor head consisting of ferro/antiferromagnetic exchange coupling multilayered films was fabricated, and its sensor characteristics were measured. Five 100-nm-thick ferromagnetic Ni-78-Fe-13-Cu-5-Mo-4 layers were multilayered between five 50-nm-thick antiferromagnetic Ir-22-Mn-78 layers by radio-frequency sputtering. The asymmetrical GMI characteristics and high sensitivity of 331 Omega/T were obtained with the sensor head. Moreover, it becomes clear that feedback control is possible with a conductive line fabricated on the sensor head. It is considered that small clearance between the sensor head and recording media can be realized by the thin-film head structure.