MEASUREMENT OF THE ELASTIC PROPERTIES OF EVAPORATED C-60 FILMS BY SURFACE ACOUSTIC-WAVES

Surface Acoustic Wave (SAW) pulses were excited in C60 films deposited on quartz and silicon substrates using pulses from excimer lasers wit h wavelengths of 248 nm and 308 nm for excitation. An optical beam-def lection technique and polymer electret transducers were utilized to de tect the propagation of the SAW pulse with high spatial and temporal r esolution, allowing an accuracy of better than 0.1% for SAW velocity m easurements. With this technique the frequency dependence of the SAW v elocity was determined for a number of fullerite films and density, as well as elastic bulk properties of the films were derived by a theore tical analysis of the dispersion effect.