The elastic and electromechanical properties of tetragonal BaTiO3 single crystals

Abstract

From velocity of sound measurements, obtained using Brillouin scattering and ultrasound techniques, the elastic and piezoelectric constants at room temperature have been determined on high-quality monodomain tetragonal BaTiO3 single crystals. The elastic constants are in fair agreement with those measured previously by the low-frequency equivalent circuit method. However, the electromechanical properties are significantly different. It is suggested that high frequency relaxation may have an influence on the measurements of those parameters.

Continuum thermodynamics of ferroelectric domain evolution: Theory, finite element implementation, and application to domain wall pinning

“…4 2 a P P P P P P P P P a a a P P P P P P P P P P P P a P P P a P P P P P P P P P a P P P P P P The properties of mono-domain single crystal barium titanate have been measured by Li et al (1991) at room temperature ( ∼ 22 o C ). For a domain with spontaneous polarization in the x 3 direction, the spontaneous polarization and strain state is In the same coordinate system, the elastic, piezoelectric, and dielectric properties given in standard Voight notation are:…”

“…Specifically, at constant strain, the ratio of the dielectric constant perpendicular to the polarization direction to the dielectric constant parallel to the polarization direction is on the order of 40 in barium titanate (Berlincourt and Jaffe, 1958;Li et al, 1991) whereas the phase-field theories used to date to model barium titanate place this ratio at about 4. With regard to the piezoelectric coefficients, previous works use the independent components of the b ijkl tensor to fit the spontaneous strain components associated with the stress and electric field free spontaneous polarization state, however no free parameters are available to fit the piezoelectric coefficients near the spontaneous state unless the g tensor is introduced.…”

First-principles computation of second-order elastic constants and equations of state for tetragonal BaTiO3

“…Therefore, the computational values of elastic constants computed with hybrid potentials are reliable if we ignore the variations in computations originating due to the order-disorder nature of the tetragonal BaTiO 3 . While comparing the results of elastic constants and bulk moduli obtained with basis set 1 vs. experimental values and basis set 2 vs. experimental values, the former shows a relatively better agreement in comparison with the latter [24][25][26][27]21]. This agreement is specifically significant in the case of a hybrid exchange and correlation potential used with basis set 1.…”

“…These variations in computational and experimental values of elastic constants and bulk moduli [24,26,28,6,21] have been constantly observed in a variety of experimental results. The causes of variation in experimental and computational values of elastic constants and bulk modulus may not be completely known.…”

“…Regarding any comparisons made of computational to experimental values, it should be noted that for this system there is a considerable variation between the experimental values of elastic constants and bulk moduli [24,25,27,21]. These variations in computational and experimental values of elastic constants and bulk moduli [24,26,28,6,21] have been constantly observed in a variety of experimental results.…”