Lattice dynamics of LiNbO3 and KNbO3

Chaplot, S. L. ; Rao, K. R. (1980) Lattice dynamics of LiNbO3 and KNbO3 Journal of Physics C: Solid State Physics, 13 (5). pp. 747-756. ISSN 0022-3719

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Official URL: http://iopscience.iop.org/0022-3719/13/5/007

Related URL: http://dx.doi.org/10.1088/0022-3719/13/5/007

Abstract

Phonon dispersion relations, in the ferroelectric phase of LiNbO3 and KNbO3, both at room temperature, are calculated using a rigid-ion model. The interatomic-potential parameters are determined on the basis of the crystal stability criterion and positivity of eigenvalues of the dynamical matrix. The computed phonon frequencies in the case of LiNbO3 match reasonably well with those from coherent inelastic neutron scattering measurements and optical measurements. The effect of varying some of the parmaeters is closely examined and it is found that, in the case of KNbO3, its soft-mode behaviour can be accounted for by suitable choice of a single parameter, namely, the effective radius of the oxygen atom lying on the b axis.

Item Type:Article
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ID Code:34763
Deposited On:11 May 2011 10:05
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