Abstract

Electrical resistivity, magnetic (saturation magnetization and switching field of the magnetic bistability) and magnetoimpedance measurements are reported in cold-drawn amorphous Fe77.5B15Si7.5 thin wires of 14 mu m diameter. Such measurements have been performed in the thin wire treated by current annealing. Electrical resistivity dependence with the intensity of the current flowing along the thin wire shows a deep decrease around 70 mA ascribed to the crystallization process. Dependence curve of the magnetization with the intensity of the current presents a change of slope at 40 mA which is ascribed to the nucleation of grains. Unusual dependence of switching field on applied stress exhibits a decrease of the switching field with the external stress in the as-prepared cold-drawn and post-treated thin wire. Magnetoimpedance ratio evolves from one to two peaks response increasing the frequency. Observed dependences interpreted taking into account strong internal stresses induced by the cold-drawn process. (C) 2009 Published by Elsevier B.V.