Temperature behaviour of optical phonons near Tc in triglycine sulphate and triglycine selenate

Schaack, G.; Winterfeldt, V.

doi:10.1080/00150197708236718

Cited by 76 publications

(34 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…I n our previous theoretical considerations [5,81 we have developed a simple nonlinear pseudospin phonon coupling to explain the observed frequency changes and critical broadening of some optical phonon modes in ferroelectric crystals. This model predicts a frequency shift for these modes, which can be written in the form…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Winterfeldt

1980

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

Raman scattering spectra of single crystals of Rochelle salt are recorded a t 2 K and a t several temperatures between 248 and 300 K in the spectral region from 0 to 4000 cm-l. The frequencies of some phonon modes soften or harden in the intermediate ferroelectric phase between the two Curie points which are known to exist in this material. I n the paraelectric phases the frequencies remain constant. This behaviour can be explained by applying a simple nonlinear pseudospinphonon coupling theory originally developed for the TGS family and the incommensurate phase transition in thiourea. The anomalous specific heat due to temperature-dependent optical phonon modes is also discussed. Es werden die Ramanspektren von Rochellesalz-Einkristallen

show abstract

Section: Experimental Methods and Resultsmentioning

confidence: 99%

“…A log-log plot of the quantity A d ( T ) actually reveals a simple power law for various phonon modes in TGS/TGSe [5] and thiourea [7 to 91. The obtained critical exponent B = 112 is in accordance with the predictions of MFA, which is well established for ferroelectrics.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Winterfeldt

1980

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

show abstract

“…We note that similar observation of strong coupling between pseudospin-phonon along with molecular deformation below transition temperature have been reported on similar systems. 14,32,33 …”

Section: -8mentioning

confidence: 99%

Evidence for phase transitions and pseudospin phonon coupling in K0.9(NH4)0.1H2AsO4

2015

View full text Add to dashboard Cite

This work reports a detailed temperature dependent Raman study on the mixed crystals of K0.9(NH4)0.1H2AsO4 (KADA) from 5K to 300K in the spectral range of 60-1200cm−1, covering tetragonal to orthorhombic structural phase transition accompanied by paraelectric to ferroelectric transition at Tc* ∼ 60K. Multiple phase transitions below transition temperature (Tc* ∼ 60K) are marked by the appearance of new modes, splitting of existing ones as well as anomalies in the self-energy parameters (i.e. mode frequencies and damping coefficient) of the phonon modes. Temperature independent behaviour of damping coefficient and abrupt jump in the mode frequency of some of the internal vibrations of AsO4 tetrahedra as well as external vibrations clearly signal long range ferroelectric ordering and proton ordering below Tc*. In addition, we observed that temperature dependence of many prominent phonon modes diverges significantly from their normal anharmonic behaviour below Tc* suggesting potential coupling between pseudospins and phonons.

show abstract

“…In fact, we examined the temperature dependence of the Raman bandwidths of this mode by calculating the damping constant in terms of the order parameter below the transition temperature (T C = 573 K) for the α-β transition in moganite. By calculating the temperature dependence of the order parameter (T < T C ) from the molecular field theory [16], the Raman bandwidths of the 501 cm −1 mode were predicted using the soft mode-hard mode coupling model [17,18] and the energy fluctuation model [19] for the α-β transition in moganite. Our calculation of the damping constant of the 501 cm −1 mode failed using both models studied since it diverges as the α-β transition temperature was approached, which was not in agreement with the observed [13] Raman bandwidths.…”

Section: Discussionmentioning

confidence: 99%

Temperature Dependence of the Raman Frequency of an Internal Mode for SiO₂-Moganite Close to theα-βTransition

Lider

Yurtseven

2012

Journal of Thermodynamics

View full text Add to dashboard Cite

show abstract

Temperature behaviour of optical phonons near Tc in triglycine sulphate and triglycine selenate

Cited by 76 publications

References 23 publications

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Evidence for phase transitions and pseudospin phonon coupling in K0.9(NH4)0.1H2AsO4

Temperature Dependence of the Raman Frequency of an Internal Mode for SiO₂-Moganite Close to theα-βTransition

Contact Info

Product

Resources

About

Temperature behaviour of optical phonons near Tc in triglycine sulphate and triglycine selenate

Cited by 76 publications

References 23 publications

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Raman Spectroscopic Investigation of Ferroelectric Phase Transitions in Rochelle Salt

Evidence for phase transitions and pseudospin phonon coupling in K0.9(NH4)0.1H2AsO4

Temperature Dependence of the Raman Frequency of an Internal Mode for SiO2-Moganite Close to theα-βTransition

Contact Info

Product

Resources

About

Temperature Dependence of the Raman Frequency of an Internal Mode for SiO₂-Moganite Close to theα-βTransition