Brillouin scattering from C-70 and C-60 films: a comparative study of elastic properties

Brillouin scattering measurements carried out on a thin film of C-70 deposi ted on a Si(100) substrate show modes at 4.8 and 25 GHz due to the surface Rayleigh wave and the bulk longitudinal acoustic mode, respectively, the co rresponding modes for C-60 being found at 4.3 and 30 GHz. Based on the Bril louin data, the values of the bulk, shear and Young's moduli of C-70 are fo und to be 11.3, 3.2 and 8.7 GPa, respectively (the corresponding values for C-60 are 14.9, 4.7 and 12.7 GPa). Poisson's ratios for Cio and C60 are com parable, the values being 0.37 and 0.36, respectively. (C) 2000 Elsevier Sc ience B.V. All rights reserved.