Defects and acoustic properties of LiAlO2

A potential piezoelectric crystal LiAlO2 with (100) orientation is grown by means of the Czochralski pulling method. The as-grown crystal is identified as a single phase with good uniformity by x-ray diffraction pattern. (001) Transmission electron microscope image showed a unique cross-hatched pattern which reveals a superlattice structure. Several cubic LiAlO2 specimen, 10.0 mmx10.0 mmx10.0 mm were manufactured to characterize its elastic properties. The time-based pulse-echo transmission technique was employed to measure the acoustic velocities of longitudinal and transverse modes. The elastic constants of LiAlO2 were extracted from the acoustic velocity measurements at different propagation directions. It was found that the acoustic velocities of LiAlO2 are much higher than the current piezoelectric crystals, including quartz, LiNbO3, and Langasite family materials. (c) 2006 American Institute of Physics.