Abstract
A distance sensor that uses a large Barkhausen effect in amorphous wires magnetized by a current is described. Helical anisotropy is created in an Fe77.5Si7.5B15 amorphous wire (cold-drawn and then tension-annealed) by applying torsion,and consequently the wire can be magnetized by the circumferential magnetic field created by the wire current. This type of distance sensor does not need a long exciting solenoid coil, and its construction is simple. The characteristics of the sensor are controlled by the number of the applied torsion. The smallest deviation from the linearity δ=0.4%/FS for a 1000mm-long wire was obtained when the value of the torsion was 10 turns/m. Domain wall motion in a twisted amorphous wire is also analyzed. The domain wall velocity increases linearly with the wire current, and its mobility decrease with increasing torsion.
