Ferroelectric lithium tantalate—2. Single crystal neutron diffraction study at 24°C

Abrahams, S. C.; Hamilton, Walter C.; Sequeira, A.

doi:10.1016/0022-3697(67)90143-6

Cited by 97 publications

(30 citation statements)

References 12 publications

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“…According to Abrahams et el. (Abrahams, Reddy & Bernstein, 1966;Abrahams, Hamilton & Reddy, 1966;Abrahams & Bernstein, 1967;Abrahams, Hamilton & Sequeira, 1967), the crystals LiNbO 3 and LiTaO 3 have the symmetry of the noncentrosymmetric space group…”

Section: Variation Of the Integrated Intensitiesmentioning

confidence: 99%

“…It is desirable to have accurate structure data, without external fields, to obtain the microscopic structural changes. Therefore, the data determined by Abrahams et aL (Abrahams, Reddy & Bernstein, 1966;Abrahams & Bernstein, 1967;Abrahams, Hamilton & Sequeira, 1967) are refined by the measurement of the ratios of the diffracted intensities of X-rays from the two opposite surfaces, (00h) and (00h). Then the observed variations of the integrated intensities, AI/I, are analysed first by assuming the ionic displacement alone and next by taking into account two other factors; one is the change in the temperature factor due to the electric-field-induced variation of phonon frequencies, and the other is the redistribution of bonding electrons of Nb-O and Ta-O bonds.…”

Section: Introductionmentioning

confidence: 99%

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Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Fujimoto¹

1982

Acta Cryst Sect A

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Electric fields with alternating square wave were applied to LiNbO 3 and LiTaO 3 single crystals in [001] directions, and extremely small ionic displacement was directly detected by the measurement of the diffracted intensities of X-rays synchronously with the applied fields. The displacement of Nb and Li ions relative to the oxygen framework were found to be 4.9 x 10 -4 and 13 x 10-4]k at E = 51.5 kV cm -1 for LiNbO 3, and those of Ta and Li to be 6.8 x 10 -4 and 15 x 10 -4 A at E = 50 kV cm -1 for LiTaO 3. The temperature factor was observed to vary with the external field, which is attributed to the change in phonon frequency of the crystal lattice. It was found from the intensity variations in the lower-indexed reflections that the displacements of the bonding electrons of Nb-O and Ta--O bonds are much larger than those of the constituent ions, which may be the origin of the electrooptic effect. The capability of the modulation technique in the absolute structure determination of crystals is demonstrated.

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Section: Variation Of the Integrated Intensitiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Fujimoto¹

1982

Acta Cryst Sect A

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“…The isomorphous compound LiTaO3, studied using single-crystal X-ray (Abrahams & Bernstein, 1967) and neutron diffraction (Abrahams, Hamilton & Sequeira, 1967), is a test-case displacement ferroelectric (Lines, 1969). Both LiNbO3 and LiTaO3 are frozen ferroelectrics (Megaw, 1954), with polarities retained by structural forces too large to be overcome by normal fields.…”

Section: Introductionmentioning

confidence: 99%

Synchrotron X-ray Studies of LiNbO₃ and LiTaO₃

Hsu¹,

Maslen²,

Boulay³

et al. 1997

Acta Crystallogr B Struct Sci

123

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“…The room-temperature crystal structure has been studied by x-ray3 and neutron diffraction 4 and they all agree that it is uniaxial trigonal belonging to the point group c3V' Ballman5 showed that the properties of many ferroelectrics have a marked dependence on the melt stoichiometry variations and particularly for Li Ta<Ja the Curie temperature may change from 540 to 700 o c, depending on the growth conditions. Above Te it is paraelectric and has a D 31 pointgroup symmetry.…”

Section: Introductionmentioning

confidence: 99%

Light scattering by lithium tantalate at room temperature

et al. 1976

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The room-temperature Raman spectra of LiTa03 for all symmetry phonons are investigated. We make a new assignment of the phonons, which agrees with the selection rules of a C3 symmetry instead of C:!V, contrary to Kaminow and Johnston's previous work. The oblique phonon dispersions are obtained and tum out to be consistent with our phonon assignments. We obtain also the polariton dispersion curve and, from it, the lowftequency dielectric constant.

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Ferroelectric lithium tantalate—2. Single crystal neutron diffraction study at 24°C

Cited by 97 publications

References 12 publications

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Synchrotron X-ray Studies of LiNbO₃ and LiTaO₃

Light scattering by lithium tantalate at room temperature

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Ferroelectric lithium tantalate—2. Single crystal neutron diffraction study at 24°C

Cited by 97 publications

References 12 publications

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO3and LiTaO3revealed by modulation X-ray diffraction

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO3and LiTaO3revealed by modulation X-ray diffraction

Synchrotron X-ray Studies of LiNbO3 and LiTaO3

Light scattering by lithium tantalate at room temperature

Contact Info

Product

Resources

About

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Electric-field-induced ionic displacement and redistribution of bonding electrons in LiNbO₃and LiTaO₃revealed by modulation X-ray diffraction

Synchrotron X-ray Studies of LiNbO₃ and LiTaO₃