Bending stresses and bistable behavior in Fe-rich amorphous wire

Abstract

The aim of this work is to analyze for the first time the changes in magnetic properties of an Fe-rich amorphous wire (Fe77.5Si7.5B15) when it is submitted to bending stresses. Upon a reduction of the radius of curvature, Rc, of the wire (i.e., increasing bending stresses), the main changes in the magnetic properties are summarized as follows: (a) Bistable behavior disappears when reducing Rc below about 11 cm but it is again observed for Rc less than about 2.5 cm. This latter effect is also obtained for short wires (less than around 7 cm) which do not show spontaneous bistability. (b) For the case when bending stresses make bistability disappear, the susceptibility increases more than one order of magnitude with regards to the case of bistable wire, and parallel to the increase of susceptibility, a reduction of remanent magnetization is observed. The disappearance and later occurrence of the bistable behavior with increasing bending stresses are discussed in terms of the tensile and compressive stresses induced when the sample is bent. The possibility of having bistable wires with toroidal symmetry is also discussed owing to its interest for particular applications as pulse generators with reduced size and magnetic switches.