ELASTIC-MODULI AND LOW-TEMPERATURE ANOMAL IES OF ACOUSTIC PROPERTIES OF HIGH-TEMPERATURE SUPERCONDUCTORS

In the review, experimental data ore given both on the propagation vel ocities of the longitudinal and transverse elastic waves and on the el astic constants of a veriety of the single crystalline and ceramic met al-oxides La2CuO4, La2-xSrxCuO4, YBa2Cu3O7-delta, Bi(Pb)-Sr-Ca-Cu-O. T he elastic moduli of isotropic polycrystals calculated by averaging th e single crystalline elastic stiffnesses of the appropriate materials and the Debye temperatures calculated from the empirical values of the acoustic wave velocities are systematized. The information on the low temperature anomalies of the acoustic properties of single crystallin e and ceramic HTSCs are summarized: the relaxation peaks of th elastic vibration attenuation, the hysteresis effects of the temperature depe ndences of the elastic moduli, the feature of the elastic characterist ics bihaviour in the vicinity of the superconducting transition. The f irst results of an investigation into elastic properties of C-60 fulle rene are discussed.