Determination of the elastic moduli in LiAlO2

Abstract

The precise determination of elastic constants of γ-LiAlO2 has recently become important, as this material is being used as a substrate for intensely studied acousto-optical device structures and no values for the elastic moduli have been published to date. The precision of experimentally determined elastic constants hinges significantly on considering the influence of the acoustic transducer on the sound propagation in the system. Therefore, the influence of the transducer is discussed and an approach for corrections is presented. The compressional elastic constants C11 and C33 and the shear constants C12 and C13 of γ-LiAlO2 are determined with an acoustic pulse-echo technique and with sampled-continuous-wave spectroscopy.

Single-crystal elastic and thermodynamic properties of γ-LiAlO2

“…ǫ σ ii /ǫ0 relative dielectric permittivity at constant stress σ, ǫ ε ii /ǫ0 relative dielectric permittivity at constant strain ε, measured at 1 MHz and valid for all three samples. The results of this study and those by Jachmann et al 8 , Takagaki et al 9 , Chou et al 7 as well as Sotnikov et al 5 , which were derived by experiments, differ considerably (table IV). Besides the fact that Jachmann et al 8 and Takagaki et al 9 published incomplete tensors of elasticity with the shear coefficients c 44 and c 66 missing, the deviations in c 11 vary between ca.…”

“…The results of this study and those by Jachmann et al 8 , Takagaki et al 9 , Chou et al 7 as well as Sotnikov et al 5 , which were derived by experiments, differ considerably (table IV). Besides the fact that Jachmann et al 8 and Takagaki et al 9 published incomplete tensors of elasticity with the shear coefficients c 44 and c 66 missing, the deviations in c 11 vary between ca. 5% (7 GPa) and 15% (13 GPa) and in c 33 between 1% (2 GPa) and 10% (18 GPa) depending on the used techique where the results derived from pulse-echo technique fits best to our results 8a .…”

“…However, despite the extended interest put by the scientific community since then in γ-LiAlO 2 , one of the basic but fundamental properties of this compound remains inconsistently and sometimes incompletely determined, i. e., the elastic coefficients. The single-crystal elastic coefficients of γ-LiAlO 2 have been determined by several research groups [7][8][9] using various acoustic measurements and mostly ultrasound pulse echo techniques. However, the data are sparse and show large variations of up to 60% in the elastic coefficients c ij .…”

High elastic modulus in b-axis-oriented single crystal V2O5

“…This expression is valid as long as the influence of the transducer attenuation can be ignored. It was shown that detailed considerations of this influence lead to considerable improvements in the otherwise highly underestimated sound-velocity [11]. In the work presented here we use this approach to follow the temperature dependent relative velocity and attenuation changes.…”