Title :
Elastic characterization of supported and unsupported Ag/Ni superlattices by Brillouin scattering
Author :
Carlotti, G. ; Fioretto, D. ; Giovannini, L. ; Socino, G. ; Rodmacq, B. ; Pelosin, V.
Author_Institution :
Dipartimento di Fisica, Perugia Univ., Italy
Abstract :
Elastic properties of Ag/Ni metallic superlattices have been investigated by means of the Brillouin light scattering technique. Measurements have been taken on both unsupported and glass-supported superlattices with periods in the range between 1 and 20 nm, prepared by DC-sputtering. Strong changes in the Rayleigh wave velocity as a function of the period have been observed and related to a softening of the effective elastic constant c44 in proximity of the interfaces. In unsupported samples, 5 μm thick, measurements of a dip in the surface phonon spectrum lead to the selective determination of c 11. This has permitted an estimation of Young´s modulus and a comparison with results obtained by conventional static techniques; no significant period-dependence has been found. In supported specimens, 0.5 μm thick, measurements of up to five acoustic guided modes have also given information on c13 and c33
Keywords :
Brillouin spectra; Rayleigh waves; Young´s modulus; crystal surface and interface vibrations; elastic constants; metallic superlattices; nickel; silver; sputtered coatings; 5 micron; Ag-Ni; Brillouin scattering; DC-sputtering; Rayleigh wave velocity; Young´s modulus; acoustic guided modes; effective elastic constant; elastic properties; glass-supported superlattices; metallic superlattices; surface phonon spectrum; unsupported Ag/Ni superlattices; Acoustic measurements; Atomic layer deposition; Brillouin scattering; Glass; Lattices; Light scattering; Metallic superlattices; Performance evaluation; Phonons; Thickness measurement;
Conference_Titel :
Ultrasonics Symposium, 1991. Proceedings., IEEE 1991
Conference_Location :
Orlando, FL
DOI :
10.1109/ULTSYM.1991.234281
