OAM-RC

Abstract

The determination and the understanding of the phenomena of elasticity in thin films are indispensable for the design and technology of various modern components. In this context, layer stiffening effects and mass loading effects are studied for several layer/substrate configurations via positive and negative dispersion curves respectively. The investigated structures showed four types of anomalies; a peak resulted of velocities greater than the Rayleigh velocity of the substrate, and a valley which is resulted of velocities smaller than the Rayleigh velocity of the layer, in the case of structures having 1 / >1/ 2 TL TS V V , as well as the inverse phenomenon, i.e. a valley comes from velocities smaller than the Rayleigh velocity of the substrate, and a peak obtained from velocities greater than the Rayleigh velocity of the layer, in the case of structures which having / >1 TL TS V V . The anomalous behaviours appeared in the dispersion curves of Rayleigh velocity are studied in terms of the extreme velocity, Ext V , which represents the maximum value of the peak, Max V , and the minimum value of the valley, Min V . The appearance and disappearance of any type of these phenomena is analysed and quantified in terms of a combined elastic parameter ( ). A general relationship which quantifies the extreme velocities in both cases, was deduced..

Keywords

Elastic properties, Thin films, Surface acoustic waves, Anomalous, Stiffening effect, Loading effect.

Citation

ABDENOUR HADDAD, Quantification of anomalous behaviour in Rayleigh velocity dispersion curves of stiffening and loading layer/substrate configurations, Optoelectronics and Advanced Materials - Rapid Communications, 7, 1-2, January-February 2013, pp.133-136 (2013).

Submitted at: Oct. 2, 2012

Accepted at: Feb. 20, 2013