Magneto-Impedance Effect in Amorphous Wire Magnetized with an Asymmetrical Current.

Abstract

New magneto-impedance characteristics were measured in FeCoSiB amorphous wires magnetized with asymmetrical wire ac currents. The wire voltage amplitude sharply increased as the applied field Hex was increased up to the anisotropy field Hk, and then gradually decreased with Hex when an ac current biased with a dc current was applied through the wire. Asymmetrical characteristics were obtained by applying an asymmetrical ac current through a twisted amorphous wire, because of the wire's spiral anisotropy. These characteristics were then used in making a linear field sensor with a pair of MI elements and no applied bias fields. A pulse response MI effects was obtained. The wire voltage due to the pulse current magnetization sharply increased with Hex during the rising and falling parts of the pulse for about 350 ns. The pulse response MI effect will be useful in establishing new magnetic recording and memory systems.