Control of Demagnetizing Field and Magnetostatic Coupling in FeCoV Wires for Zero-Speed Sensor

A fast magnetization reversal in twisted Vicalloy wires is utilized in speed sensor, rotation sensor, and other applications. It has the advantage of generating a constant pulse voltage in a pickup coil which is independent of a changing rate of the applied magnetic field. But the demagnetizing field and magnetostatic coupling at both ends of the wire prevent desirable conditions of excitation magnets and symmetric output voltage in the sensor application. We have achieved improvements in the output voltage and the condition of the exciting magnetic field by using the twisted Vicalloy wire whose outer layer at both ends is etched