INTERDIGITAL TRANSDUCER APPLICATION FOR ULTRASONIC STUDY OF SRTIO3 INTHE QUANTUM PARAELECTRIC REGION

The method of bulk acoustic wave excitation by means of electrostricti ve interdigital transducers has been used to study acoustic anomalies in the quantum paraelectric state of SrTiO3 below 40 K. The applicatio n of an external electric field during cooling below the structural ph ase transition at 105 K was found to be essential for low-distorted ac oustic wave fronts which are necessary for high accuracy acoustic puls e measurements. The measured temperature dependence of pulse delay tim e can be related to TA-branch suppression caused by repulsing between soft optical and acoustic modes.