Spontaneous Ac Field Induced Mechanical Rotation in Magnetostrictive Fesib-Based Wires Subjected to Thermal Treatments

Abstract

ABSTRACTAn astonishing new phenomenon has been recently observed in magnetic wires. It consists of the spontaneous rotation of the wires when submitted to an exciting AC axial field with frequency of the order of kHz and amplitude above some threshold. The rotation is believed to appear due to interaction between generated magnetoelastic standing waves and induced eddy currents. In the present work rotational characteristics of Fe77.5Si7.5B15 and Fe73.5Si13.5B9Cu1Nb3wires in their as-cast amorphous state and after heat treatments leading to devitrification has been investigated. It is proved that this rotational phenomenon is only observed in samples with large enough magnetostriction irrespective of their structural character. Moreover, changes in rotational characteristics are ascribed to the structural modifications accompanying the devitrification process.