Fabrication of acoustic superlattice LiNbO3 by pulsed current induction and its application for crossed field ultrasonic excitation

An acoustic superlattice LiNbO3 crystal with periodic ferroelectric domain structure was fabricated by introducing a periodic electric current through the solid-liquid interface during the crystal growing process. The domain morphology of an as-grown crystal was observed with a scanning electron mic roscope, and was found to be of good periodicity. A light diffraction exper iment indicated that there was a periodic fluctuation of the dielectric con stant along the crystal's growing direction. Using the "crossed field" sche me, a 340 MHz ultrasonic was excited in the crystal, which means that the a coustic superlattice is suitable for constructing high-frequency bulk-wave acoustic devices. (C) 2000 American Institute of Physics. [S0003-6951(00)05 038-5].