IOP Conference Series: Materials Science and Engineering, 2010
ABSTRACT The propagation of ultrasonic waves is still a topic of interest due to its applications... more ABSTRACT The propagation of ultrasonic waves is still a topic of interest due to its applications in surface acoustic wave devices (SAW). Research works related to propagation in various media as multilayer, thin film and semi infinite media can be found in the recent literature. Applications of these studies include technological areas as electronic systems and sensors. Acoustic wave propagation in piezoelectric media is basically achieved by the use of the ordinary differential equations method ODE. Our purpose is to elucidate how ODE is carried out leading to a best identification of the involved electromechanical partial waves. The eigenvector equation related to ODE method has been solved in three cases depending on the symmetry of the sagittal plane. Therefore the fundamental acoustic tensor is reformulated with respect to the existing coupling between the elastic partial waves and the electrical one. The new formulation of ODE is useful during propagation studies either in elastic materials or piezoelectric ones. The obtained results are illustrated on the well known piezoelectric material ZnO, which is assumed to be hexagonal.
Ahmed Elantably b a Research Unit on Renewable Energies and Electric Vehicles University of Sfax,... more Ahmed Elantably b a Research Unit on Renewable Energies and Electric Vehicles University of Sfax, Sfax Engineering School BP W, 3038 Sfax, Tunisia Tel.: +216 74 274 088; Fax: +216 74 275 595; E-mail: a.masmoudi@enis.rnu.tn b Allison Transmission Division of General ...
ABSTRACT In this work, we report the studies on piezoelectric properties of epitaxial ZnO thin fi... more ABSTRACT In this work, we report the studies on piezoelectric properties of epitaxial ZnO thin films grown on R-Al2O3 and C-Al2O3 substrates using plasma-assisted molecular beam epitaxy (MBE). The resulting relationships are found with φ-scans and X-ray diff raction. The epitaxial relationship for ZnO films on R-Al2O3 and C-Al2O3 substrates are found to be (1120)[0001]ZnO//(0112)[0111]R–AL2O3 and (0001)[1010]ZnO//(0001)[2110]C–AL2O3, respectively Appropriate dispersion curves relative to Rayleigh waves, for both configurations ZnO/R-Al2O3 and ZnO/C-Al2O3 have been recorded in the frequency range up to 200 MHz utilizing laser ultrasonic equipment. Surface acoustic wave (SAW) propagation in piezoelectric media is basically achieved by the use of the ordinary diff erential equations method ODE, the generalized stiff ness matrix method GSMM and Green's function. These methods are reformulated with respect to the existing decoupling between the sagittal-plane displacement and the transverse displacement with respect to the electric potential. SAW properties, including dispersion curves and electromechanical coupling factor, are characterized. The cut-off velocity of the higher Rayleigh mode for both configurations is diff erent from the corresponding transverse bulk wave. The adopted elastic constants during numerical simulations are obtained from the literature. The positive sign of the elastic coefficient C14 of sapphire has been adjusted on the basis of ultrasonic measurements. The obtained results set guidelines for the design of high-frequency and low-loss SAW devices.
IOP Conference Series: Materials Science and Engineering, 2010
ABSTRACT The propagation of ultrasonic waves is still a topic of interest due to its applications... more ABSTRACT The propagation of ultrasonic waves is still a topic of interest due to its applications in surface acoustic wave devices (SAW). Research works related to propagation in various media as multilayer, thin film and semi infinite media can be found in the recent literature. Applications of these studies include technological areas as electronic systems and sensors. Acoustic wave propagation in piezoelectric media is basically achieved by the use of the ordinary differential equations method ODE. Our purpose is to elucidate how ODE is carried out leading to a best identification of the involved electromechanical partial waves. The eigenvector equation related to ODE method has been solved in three cases depending on the symmetry of the sagittal plane. Therefore the fundamental acoustic tensor is reformulated with respect to the existing coupling between the elastic partial waves and the electrical one. The new formulation of ODE is useful during propagation studies either in elastic materials or piezoelectric ones. The obtained results are illustrated on the well known piezoelectric material ZnO, which is assumed to be hexagonal.
Ahmed Elantably b a Research Unit on Renewable Energies and Electric Vehicles University of Sfax,... more Ahmed Elantably b a Research Unit on Renewable Energies and Electric Vehicles University of Sfax, Sfax Engineering School BP W, 3038 Sfax, Tunisia Tel.: +216 74 274 088; Fax: +216 74 275 595; E-mail: a.masmoudi@enis.rnu.tn b Allison Transmission Division of General ...
ABSTRACT In this work, we report the studies on piezoelectric properties of epitaxial ZnO thin fi... more ABSTRACT In this work, we report the studies on piezoelectric properties of epitaxial ZnO thin films grown on R-Al2O3 and C-Al2O3 substrates using plasma-assisted molecular beam epitaxy (MBE). The resulting relationships are found with φ-scans and X-ray diff raction. The epitaxial relationship for ZnO films on R-Al2O3 and C-Al2O3 substrates are found to be (1120)[0001]ZnO//(0112)[0111]R–AL2O3 and (0001)[1010]ZnO//(0001)[2110]C–AL2O3, respectively Appropriate dispersion curves relative to Rayleigh waves, for both configurations ZnO/R-Al2O3 and ZnO/C-Al2O3 have been recorded in the frequency range up to 200 MHz utilizing laser ultrasonic equipment. Surface acoustic wave (SAW) propagation in piezoelectric media is basically achieved by the use of the ordinary diff erential equations method ODE, the generalized stiff ness matrix method GSMM and Green's function. These methods are reformulated with respect to the existing decoupling between the sagittal-plane displacement and the transverse displacement with respect to the electric potential. SAW properties, including dispersion curves and electromechanical coupling factor, are characterized. The cut-off velocity of the higher Rayleigh mode for both configurations is diff erent from the corresponding transverse bulk wave. The adopted elastic constants during numerical simulations are obtained from the literature. The positive sign of the elastic coefficient C14 of sapphire has been adjusted on the basis of ultrasonic measurements. The obtained results set guidelines for the design of high-frequency and low-loss SAW devices.
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