Acoustic studies of new materials: Quasicrystals, low-loss glasses, and high T(sub c) conductors

The goals of this project involve the development and application of new techniques in acoustics. The goals are: (1) to study the properties of single crystal high temperature superconductor oxide materials with ultrasonic measurements; (2) to study the properties of quasicrystals using ultrasound and acoustic analog systems; and (3) to develop and apply a new resonant photoacoustic technique to measure optical absorption in very low loss glasses and crystals. Major accomplishments include the development of a new method of ultrasound measurement which permits the determination of all of the independent elastic constants of very small samples (a few hundred microns in size), the use of the apparatus to study high temperature superconductor material and aluminum alloy quasicrystals, and the development and test of a new technique for measuring optical absorption with more than an order of magnitude improvement in sensitivity over existing methods.