https://doi.org/10.1140/epjb/e2009-00423-9
Piezoelastic properties of retgersite determined by ultrasonic measurements
1
Institut für Geowissenschaften, Abt. Kristallographie, Goethe Universität Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany
2
Institut für Kristallographie, Universität zu Köln, Zülpicher Str. 49b, 50674 Köln, Germany
3
Accelrys Inc., 334 Cambridge Science Park, Cambridge CB4 0WN, UK
Corresponding author: arbeck@kristall.uni-frankfurt.de
Received:
4
August
2009
Revised:
4
October
2009
Published online:
11
December
2009
The elastic tensor of the tetragonal NiSO4 . 6H2O (retgersite) was measured with a resonant ultrasonic plane parallel plate technique at room temperature as a function of hydrostatic pressure in the range of 0.1-50 MPa and the piezoelastic coefficients have been derived. The monotonic increase in the cij shows that retgersite does not undergo a phase transition in this pressure range. Density functional theory (DFT) based calculations within the linear response method were used to predict the variation of the cij in the range of 1-1000 MPa in the static limit. A comparison of the two data sets shows that while structural parameters and elastic stiffness coefficients are well reproduced by the DFT model, theoretical piezoelastic coefficients of compressible compounds are only in moderate agreement with the corresponding experimental values. The limitations of DFT-based calculations for the calculation of piezoelastic coefficients are discussed.
PACS: 62.20.D- – Elasticity / 62.20.dq – Other elastic constants / 43.35.Cg – Ultrasonic velocity, dispersion, scattering, diffraction, and attenuation in solids; elastic constants
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009
