Articles you may be interested inIntrinsic anomalous ferroelectricity in vertically aligned LiNbO3-type ZnSnO3 hybrid nanoparticle-nanowire arrays Appl. Phys. Lett. 105, 212903 (2014); 10.1063/1.4902557 40-50MHz lithium niobate (LiNbO3) transducers for pulsed Doppler measurements in mouse embryos Acoustic and optic phonons have been measured by Brillouin and Raman spectroscopies in LiNbO 3 samples with different stoichiometries. Consequently, the elastic constants have been determined by Brillouin scattering as a function of the stoichiometry. The C 44 elastic constant presents, as a function of the stoichiometry, a clear minimum for the ͓Li͔/͓Nb͔ϭ1 in the melt sample. This behavior must be related to the existence and competition of two kind of defects, i.e., extended defects induced when growing samples not at the congruent composition, and point defects present in nonstoichiometric samples. The optic phonons seem to be dominated by the point defects. The linear increase of the phonon lifetimes, with respect to an ideal stoichiometric sample, can be due to the scattering by the static imperfections and to an increase of the anharmonic scattering. Several Raman peaks, which appear when the ͓Li͔/͓Nb͔ ratio decreases, are related to the presence of Nb in antisites. The width of some particular phonons can be used to estimate the ͓Li͔/͓Nb͔ ratio whenever a line shape study and a good correction, taking into account the instrumental broadening, is carried out.

The elastic constant tensors of thin layers of InxGa1-xAs and InxGa1-xP with compositions around x = 0.5 have been determined using surface acoustic waves measured by Brillouin light scattering spectroscopy. Contrary to the case for the usual estimates, the experimentally obtained elastic constants are different from the ones calculated by simple linear combination of those of the corresponding constituent binary compounds. An averaging model combining a parallel-serial disposition of springs with the elastic constants corresponding to the binary compounds has been used to explain the elastic constants of the ternary alloys. This model explains perfectly the elastic properties of the InxGa1-xAs system, while those of the InxGa1-xP system are not reproduced.

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