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Brody, Edward M.; Cummins, H. Z.

doi:10.1103/physrevlett.21.1263

Cited by 164 publications

(36 citation statements)

References 11 publications

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“…Elastic properties of the KDP crystal have been investigated for the frequencies ranging from hertz to gigahertz [82,[91][92][93][94][95][96][97]. The analysis of results of the investigation presented in this section is made for the two frequency ranges: from gigahertz to 100 kHz and for the frequencies of an order of hertz.…”

Section: Resultsmentioning

confidence: 99%

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Wiesner

2009

Phase Transitions

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The experiments reported in this article have been performed to unify the results of earlier and recent determinations of parameters describing the elastic properties of Rb 4 LiH 3 (SO 4 ) 4 , LiCsSO 4 (LCS) and KH 2 PO 4 crystals measured by different experimental methods. The above crystals undergo a second-order phase transition, incommensurate phase transition (PT) and a first-order but close to second-order phase transition, respectively. To investigate the elastic properties of the crystals in the frequency range from 10 À1 to 10 10 Hz, five experimental methods were applied: dynamic mechanical analysis, piezoelectric resonance, composite oscillator bar, ultrasonic wave propagation and Brillouin light scattering. The results of the experiments allowed identification of the processes contributing to the elastic response of the crystals investigated. Moreover, for the LCS crystal a model of the incommensurate PT was presented.

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Section: Resultsmentioning

confidence: 99%

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Wiesner

2009

Phase Transitions

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“…Softening in elastic constants was reported in several types of single crystal ceramics [25][26][27] when they undergo phase transitions while electrically short-circuited. As for the BaTiO 3 -Sn composite material, a portion of particles are able to exist in the form of single crystals.…”

Section: Originalmentioning

confidence: 98%

Broadband viscoelastic spectroscopy measurement of mechanical loss and modulus of polycrystalline BaTiO₃ vs. temperature and frequency

Stone

Lakes

2008

Physica Status Solidi (b)

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Characterization of pure polycrystalline BaTiO3 was carried out by means of Broadband Viscoelastic Spectroscopy (BVS) and Differential Scanning Calorimetry (DSC) above ambient temperature. A peak in mechanical loss has been observed near the Curie point 130 °C. The magnitude of the peak increases with thermal rate and decreases with frequency. Expressions for the peak magnitude have been derived based upon available models describing the first order phase transition. Mechanical anomalies were observed outside the vicinity of the phase transition. Transition temperature measured by BVS differed from that via DSC; the effect of stress on the ferroelastic transformation is a possible cause. Isothermal frequency scans revealed a hump in mechanical loss in the vicinity of the transition temperature below 1 Hz and a modulus decrease with decreasing frequency. Quasi‐isothermal studies revealed a significant softening in bulk modulus and a transient negative Poisson's ratio during the tetragonal‐to‐cubic phase transition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…* From the definitions of a, b, c (16) it is possible to verify that condition (19) implies d e t r = 0 (i.e. r a b = d / r a r&.…”

Section: Indirect Coupling Of Two Optic Phonons Via Third-order Anharmentioning

confidence: 99%

Indirect coupling of the soft optic phonon in KH₂PO₄

Mazzacurati¹,

Signorelli²,

Sampoli

1976

J Raman Spectroscopy

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The shape of the low frequency first-order Raman spectrum of KDP single crystals in the x ( y , x)y configuration is discussed. Two and three coupled oscillators modds are used to explain the spectral region up to 270 cm-l. The inadequacy of such models in describing the experimental data is analyzed, and a model in which two optic phonons are coupled via their decay into two acoustic phonons is proposed. The spectra in the para-electric phase are thus well accounted for by a soft optic phonon interacting via the two-phonon continuum with a temperature-independent lattice mode. This picture is found to be consistent with a quite reasonable shape of the joint-density of states for the acoustic phonons. Finally the proton-phonon interaction hypothesis is briefly reconsidered from this point of view.

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Brillouin-Scattering Study of the Ferroelectric Transition in KH2PO4

Cited by 164 publications

References 11 publications

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Broadband viscoelastic spectroscopy measurement of mechanical loss and modulus of polycrystalline BaTiO₃ vs. temperature and frequency

Indirect coupling of the soft optic phonon in KH₂PO₄

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Brillouin-Scattering Study of the Ferroelectric Transition in KH2PO4

Cited by 164 publications

References 11 publications

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Ferroelastic crystals and their nonlinear elastic properties observed in frequency range from gigahertz to milihertz

Broadband viscoelastic spectroscopy measurement of mechanical loss and modulus of polycrystalline BaTiO3 vs. temperature and frequency

Indirect coupling of the soft optic phonon in KH2PO4

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Broadband viscoelastic spectroscopy measurement of mechanical loss and modulus of polycrystalline BaTiO₃ vs. temperature and frequency

Indirect coupling of the soft optic phonon in KH₂PO₄