| 摘要 |
PURPOSE:To make possible controlling of time intervals of elastic wave pulse trains of bulk longitudinal wave mode by providing zigzag thin film linear conductors on an amorphous magnetostrictive thin plate and applying vaiable bias magnetic fields. CONSTITUTION:A coil 2 is provided to an amorphous magnetostrictive thin plate 1 by forming thin film linear conductors of a conductor width larger than the plate thickness of the thin plate 1 in zigzag form and a variable control type bias magnetic field applying device composed of a solenoid coil 3 and a magnetic yoke 4 is provided in the installation position thereof. When signal current is flown to this coil 2, the combined magnetic fields of the magnetic field of the coil 2 and the bias magnetic field of the coil 3 are formed as a positive and negative magnetic field distribution with the bias magnetic field as a center at a certain instant, then strains are generated in the thin plate 1, becoming a elastic wave pulse train. The time interval deltaT of this pulse train is deltaT=P/v where the interline spacing of the coil 2 is let to be p, and the velocity of sound of the thin plate 1 to be v. The velocity of sound (v) changes with the bias magnetic fields owing to the macro deltaE effect of the thin film 1. Namely, even if (p) is constant, the velocity of sound (v) increases and the pulse train interval deltaT decreases as the intensity of the bias magnetic field increases. |
