Bending effects and temperature dependence of magnetic properties in a Fe-rich amorphous wire

Amorphous wires with composition Fe77.5Si7.5B15 exhibit a very peculiar mag netization process characterized by a single and quite large Barkhausen jum p. This gives rise to a squared hysteresis loop at a critical magnetic fiel d. The bistable behaviour, widely studied in wires with typical length of 1 0 cm and diameter of 125 mum, appears above a length of about 7 cm in strai ght wires and disappears for curvature radius within the range 2-12 cm in b ent wires. In this work it is shown that bistability occurs in bent wires, whatever their curvature is, provided the wires are long enough. To this pu rpose spiral-shaped samples with several turns are considered. However, whe n the wire length is not a integer number of turns the magnetization revers es through many large Barkhausen jumps. In this condition, varying the meas uring temperature can activate the energy barriers for the jumps. (C) 2001 Elsevier Science B.V. All rights reserved.