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Physics Letters A, 2004
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Soft modes in relaxor ferroelectrics
Phase Transitions, 1981Abstract The fact that the polarization-related electrostrictive coefficients Q in the relaxor type ferro-electrics are almost an order of magnitude smaller than in most normal ferroelectric perovskites can be explained under the assumption that the temperature dependence of the soft-mode TO phonon frequency is given as ω2 TO = A(T — Tc ), where the ...
K. Uchino +3 more
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Journal of the Physical Society of Japan, 1973
The spin-wave theory is developed for the study of the acoustic soft-magnon modes in hematite (α-Fe 2 O 3 ). The energies ω 0 of the soft-modes are approximately given as ω 0 ∞| T M - T | 1/2 near the Morin phase transition temperature T M and the results are compared with the AFMR experiments.
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The spin-wave theory is developed for the study of the acoustic soft-magnon modes in hematite (α-Fe 2 O 3 ). The energies ω 0 of the soft-modes are approximately given as ω 0 ∞| T M - T | 1/2 near the Morin phase transition temperature T M and the results are compared with the AFMR experiments.
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Philosophical Magazine B, 2001
Abstract The concept of atomic soft modes in glass dynamics and general assumptions and some basic results of the soft-mode dynamics theory of glasses are discussed in the light shed by experimental observations. Negative- U centres as actual electronic mobility-gap centres, vast pressure-induced effects in dynamics, quasilinear frequency dependence of
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Abstract The concept of atomic soft modes in glass dynamics and general assumptions and some basic results of the soft-mode dynamics theory of glasses are discussed in the light shed by experimental observations. Negative- U centres as actual electronic mobility-gap centres, vast pressure-induced effects in dynamics, quasilinear frequency dependence of
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Time-domain soft mode spectroscopy
Ferroelectrics, 1991Abstract The application of impulsive stimulated light scattering, an entirely time-domain form of light scattering spectroscopy, to the study of lattice dynamics in crystals near structural phase transitions is reviewed. Advantages of the time-domain approach are demonstrated for study of low-frequency, heavily damped, and/or dispersive modes such as ...
Lap-Tak Cheng, Keith A. Nelson
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Soft Modes in Molecular Crystals
The Journal of Chemical Physics, 1971The self-consistent phonon approximation is applied to study the temperature dependence of the libron and phonon modes for simple molecular crystals. Several linear chain models are studied to illustrate the soft mode behavior of these excitations near the orientational order—disorder transitions that occur in many molecular crystals.
J. C. Raich, R. D. Etters
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Physical Review Letters, 1969
The self-consistent phonon formalism, successful in the description of the quantum crystals ${\mathrm{He}}^{3}$ and ${\mathrm{He}}^{4}$, is here applied to a discussion of the soft $k=0$ TO mode in SnTe. Straightforward considerations allow us to arrive at a simple expression for $\ensuremath{\omega}_{\mathrm{TO}}^{}{}_{}{}^{2}(k=0)$ in the low ...
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The self-consistent phonon formalism, successful in the description of the quantum crystals ${\mathrm{He}}^{3}$ and ${\mathrm{He}}^{4}$, is here applied to a discussion of the soft $k=0$ TO mode in SnTe. Straightforward considerations allow us to arrive at a simple expression for $\ensuremath{\omega}_{\mathrm{TO}}^{}{}_{}{}^{2}(k=0)$ in the low ...
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SPIE Proceedings, 1990
SINGLE -MODE SOFT GLASS FIBRESKazimierz JedrzejewskiInstitute of Electronics Fundamentals, Warsaw University of Technology00 -665 Warszawa, Nowowiejska 15/19ABSTRACTThe technology of single -mode optical soft glass fibres is developed. The well -known rodin tube technique with multiple sleeving was taken to achieve proper dimensions.
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SINGLE -MODE SOFT GLASS FIBRESKazimierz JedrzejewskiInstitute of Electronics Fundamentals, Warsaw University of Technology00 -665 Warszawa, Nowowiejska 15/19ABSTRACTThe technology of single -mode optical soft glass fibres is developed. The well -known rodin tube technique with multiple sleeving was taken to achieve proper dimensions.
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Soft modes, a personal perspective
Ferroelectrics, 1981Abstract The early history of the concept of soft modes is reviewed, with some reflections on its delayed impact and on multiple independent discovery.
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Soft mode induced structural instabilities
Ferroelectrics, 1992Abstract Structural instabilities and especially those which are related to polar instabilities and ferroelectric phase transitions are investigated within a modified φ4-model. Instead of describing these types of phase transitions within a rigid ion model with anharmonic ion-ion interactions the electronic degrees of freedom are seriously taken into ...
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