scholarly journals Origin of Piezoelectricity in Piezoelectric Ceramics from the Viewpoints of Elastic Constants Measured by Acoustic Wave Velocities

10.5772/60793 ◽  
2015 ◽  
Author(s):  
Toshio Ogawa
Keyword(s):  
Acoustic Wave ◽  
Elastic Constants ◽  
Piezoelectric Ceramics ◽  
Wave Velocities

scholarly journals Theoretical investigation of acoustic wave velocity of aluminum phosphide under pressure

2019 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Salah Daoud ◽  
Abdelhakim Latreche ◽  
Pawan Kumar Saini
Keyword(s):  
Acoustic Wave ◽  
Wave Velocity ◽  
Elastic Constants ◽  
Structural Parameters ◽  
Theoretical Data ◽  
Aluminum Phosphide ◽  
Semiconducting Material ◽  
Wave Velocities ◽  
Knoop Microhardness ◽  
Good Agreement

The bulk and surface acoustic wave velocities of Aluminum phosphide (AlP) semiconducting material under pressure up to 9.5 GPa were studied. The structural parameters and the elastic constants used in this work are taken from our previous paper published in J. Optoelec-tron. Adv. M. 16, 207 (2014). The results obtained at zero-pressure are analyzed and compared with other data of the literature. In addition, the acoustic Grüneisen parameter and the Vickers and Knoop microhardness are predicted and analyzed in detail. Our calculated results are in good agreement with the experimental and other theoretical data of literature.   

ELASTIC CONSTANTS AND ACOUSTIC WAVE VELOCITIES IN Cd1-xZnxTe MIXED CRYSTALS

2008 ◽  
Vol 22 (12) ◽  
pp. 1221-1229 ◽  
Author(s):  
N. BOUARISSA ◽  
Y. ATIK
Keyword(s):  
Acoustic Wave ◽  
Elastic Constants ◽  
Mixed Crystals ◽  
Bulk Acoustic Wave ◽  
Virtual Crystal Approximation ◽  
Wave Speeds ◽  
Wave Velocities ◽  
Zinc Blende ◽  
Compositional Disorder ◽  
Zinc Blende Structure

Based on the pseudopotential scheme under the virtual crystal approximation that takes into account the effect of compositional disorder combined with the bond-orbital model of Harrison, the results of calculations of elastic constants and surface and bulk acoustic wave speeds of Cd 1-x Zn x Te mixed crystals in the zinc-blende structure are presented. The agreement between our results and known data, which are only available for CdTe and ZnTe is found to be reasonable.

How Can Be Realized High Piezoelectricity from Measuring Acoustic Wave Velocities ?

2014 ◽  
Vol 90 ◽  
pp. 33-42
Author(s):  
Toshio Ogawa
Keyword(s):  
Acoustic Wave ◽  
Wave Velocity ◽  
Piezoelectric Materials ◽  
Piezoelectric Ceramics ◽  
Measuring Method ◽  
Lead Free ◽  
Material Research ◽  
Thickness Gauge ◽  
Wave Velocities ◽  
Lead Free Ceramics

Material research and development on piezoelectric ceramics, especially lead-free ceramics, was proposed from a viewpoint of relationships between piezoelectricity and elastic constants such as Young’s modulus and Poisson’s ratio. We developed a method to be convenient to measure acoustic wave velocities by an ultrasonic thickness gauge with high-frequency. From the change in longitudinal and transvers wave velocities before and after DC poling, it was found that the ceramic bulk density was important to improve the piezoelectricity in lead-free ceramics. As a result, the candidates of lead-free ceramic compositions with higher piezoelectricity were proposed. Furthermore, the ratio of transvers wave velocity to longitudinal wave velocity was clarified to estimate compositions with higher piezoelectricity. The measurement of sound velocities was an effective method for researching and developing piezoelectric materials, and it was possible to design the material compositions of lead-free piezoelectric ceramics as well as lead-containing ceramics by the novel measuring method.

Acoustic waves I

2004 ◽  
Author(s):  
Robert E. Newnham
Keyword(s):  
Acoustic Wave ◽  
Elastic Constants ◽  
Acoustic Waves ◽  
Shear Waves ◽  
Plane Waves ◽  
Volume Element ◽  
Longitudinal Waves ◽  
Stress Gradients ◽  
Wave Velocities ◽  
Wave Normal

In this chapter we treat plane waves specified by a wave normal and a particle motion vector . Two types of waves, longitudinal waves and shear waves, are observed in solids. For low symmetry directions, there are generally three different waves with the same wave normal, a longitudinal wave and two shear waves. The particle motions in the three waves are perpendicular to one another. Only longitudinal waves are present in liquids because of their inability to support shear stresses. The transverse waves are strongly absorbed. Acoustic wave velocities (v) are controlled by elastic constants (c) and density (ρ). For a stiff ceramic (c ∼ 5 × 1011 N/m2) and density (ρ ∼ 5 g/cm3 = 5000 kg/m3), the wave velocity is about 104 m/s. For low frequency vibrations near 1 kHz the wavelength λ is about 10 m. The shortest wavelengths are around 1 nm and correspond to infrared vibrations of 1013 Hz. Acoustic wave velocities for polycrystalline alkali metals are plotted in Fig. 23.2. Longitudinal waves travel at about twice the speed of transverse shear waves since c11 > c44. Sound is transmitted faster in light metals like Li which have shorter, stronger bonds and lower density than heavy alkali atoms like Cs. The tensor relation between velocity and elastic constants is derived using Newton’s Laws and the differential volume element shown in Fig. 23.3(a). The volume is equal to (δZ1) (δZ2) (δZ3). Acoustic waves are characterized by regions of compression and rarefaction because of the periodic particle displacements associated with the wave. These displacements are caused by the inhomogeneous stresses emanating from the source of the sound. In tensor form the components of the stress gradient are ∂Xij/∂Zk and will include both tensile stress gradients and shear stress gradients, as pictured in Fig. 23.3(b). The force F acting on the volume element is calculated by multiplying the stress components by the area of the faces on which the force acts.

Contactless ultrasonic device to measure surface acoustic wave velocities versus temperature

2007 ◽  
Vol 78 (2) ◽  
pp. 024901 ◽  
Author(s):  
C. Hubert ◽  
M.-H. Nadal ◽  
G. Ravel-Chapuis ◽  
R. Oltra
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Ultrasonic Device ◽  
Wave Velocities
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