Theory of giant ΔE effect in magnetostrictive amorphous ribbons

A phenomelogical theory is given of the magnetoelastic coupling to account for the giant ΔE effect observed in highly magnetostrictive amorphous ribbons by changing a bias field. This effect is intrinsic and is formulated by simultaneous second order differential equations in which the high magnetoelastic coupling together with the high permeable properties play essential roles. This theory gives the principle of operating the sound transmission elements, such as continuously variable delay line and tunable magnetostrictive transducer.