Large Barkhausen effect and Matteucci effect in cold-drawn amorphous magnetostrictive wires.

Abstract

Reinforced Large Barkhausen effect and the Matteucci effect are realized applying a tension anneal to cold drawn amorphous magnetostrictive wires (Fe77.5Si7.5B15 made by Unitika Co.). Sharpness and the amplitude of induced voltage pulses at the pick-up coil of the amorphous wire are proportional to the value of H*-H0, where H* is the critical field of domain nucleation at the flux reversal, and H0 is the critical field of domain-wall displacement. The value of H*-H0 increased about ten times that of as-prepared wires. The Matteucci voltage was also increased in the tension annealed cold drawn wires. The critical length of the wire which shows the large Barkhausen effect could be reduced to about 20 mm (60mm for as-prepared wires). Therefore, small-sized rotation sensors are realized using the new wires.