STUDY OF VIBRATIONAL DYNAMICS OF Ca-BASED METALLIC GLASSES BY PSEUDOPOTENTIAL THEORY

摘要

The vibrational dynamics of three Ca-based metallic glasses viz. Ca_(70)Mg_(30), Ca_(70)Zn_(30) and Ca_(30)Al_(40) have been studied at room temperature in terms of the phonon eigen frequencies of longitudinal and transverse modes, employing three theoretical formulations given by Hubbard-Beeby (HB), Takeno-Goda (TG) and Bhatia-Singh (BS). Five local field correction functions viz. Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used for the first time in the present investigation to study the screening influence on the aforesaid properties. Long wavelength limits of the phonon modes are then used to get information on the elastic and thermal properties of the system. The low temperature specific heat is also calculated from the elastic limit of the phonon dispersion curves. The present results agree satisfactory with the experimental as well as theoretical values.