Effect of Annealing on Generation of Magnetoelastic Waves in Amorphous Wires, and Their Application

The effect of annealing on the generation and detection characteristics of magnetoelastic waves (MEWs) in Fe77.5Si7.5B15 amorphous wires was studied. Annealing after wire-drawing was found to be exceedingly effective in improving the efficiency in high-frequency regions. The wire-drawing is indispensable to eliminate inhomogeneities which may scatter the high-frequency MEWs. The annealing is necessary to soften the magnetic hardness arising from the wire-drawing. It was found that a partial annealing causes a small region, highly sensitive to a driving magnetic field, to develop; this region is made insensitive to the driving field by wire-drawing. The small region serves as an excellent source for generating high-frequency MEWs.