Magnetostrictive influence on the bistability of amorphous wires

We have studied the effect of tension and external field on the magnetization process in amorphous positive magnetostrictive Fe-Si-B wires. The radial stress created during the in-rotating water quenching technique of producing these wires causes a radial anisotropy. Using a simple phenomenological model which assumes a continuous distribution for the values of these radial stresses, we fit the observed values of the remanence as a function of the applied longitudinal stress and obtain information about the stress distribution. We also explain in a consistent manner the dependence of the magnetization process on the applied longitudinal stress. On doing so, a value of the saturation magnetostriction constant λs=28×10−6 is obtained for a Fe77.5Si7.5B15 amorphous wire. In the stress dependence of the nucleation field for the Barkhausen jump we observe a minimum. A quantitative explanation for this minimum is given.