Quasi-elastic light scattering in KTa/sub 1-x/Nb/sub x/O/sub 3/

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 1984

OSTI ID:5740087

Lee, E

The ferroelectric phase transition in the mixed crystal system KTa/sub 1-x/Nb/sub x/O/sub 3/ (KTN) was studied using inelastic light scattering techniques. A quasi-elastic scattering peak centered at zero frequency shift was discovered in the light scattering spectrum of KTN samples containing approx. =3% and 10% Nb. Elastically scattered light was attenuated several orders of magnitude by a molecular iodine filter, which has a resonant absorption line at the wavelength of the laser excitation (5145 A in an argon-ion laser), thereby allowing the study of low frequency spectral features. High resolution Brillouin scattering measurements revealed a finite, minimum width of approx. = 5.6 GHz for the quasi-elastic component in spectra that were corrected for subsidiary iodine absorptions. The line shape of the central peak, as observed in these Brillouin measurements, was non-Lorentzian. Because previous central peak research in other materials attributed this scattering to a coupling of the soft TO phonon mode to a slowly relaxing internal degree of freedom, Raman scattering experiments were also performed to study the intensity of the central peak relative to the intensity of the soft mode. In the Raman measurements, the frequency width of the very narrow central peak component could not be resolved, although a broader frequency component could be discerned in the spectra.

• Research Organization: Indiana Univ., Bloomington (USA)
• OSTI ID: 5740087
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FERROELECTRIC MATERIALS
PHASE TRANSFORMATIONS
NIOBATES
LIGHT SCATTERING
POTASSIUM COMPOUNDS
TANTALATES
BRILLOUIN EFFECT
RAMAN EFFECT
ALKALI METAL COMPOUNDS
COHERENT SCATTERING
NIOBIUM COMPOUNDS
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
TANTALUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360602* - Other Materials- Structure & Phase Studies