Polarized XAFS Study of KNbO<sub><b>3</b></sub>Local Structure

Shuvaeva, V. A.; Yanagi, Koichiro; Sakaue, Kiyoshi; Terauchi, Hikaru

doi:10.1143/jpsj.66.1351

Cited by 6 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In disagreement with our XAFS results, Shuvaeva, et al [37,38], using polarized XAFS and X-ray diffraction measurements of the single crystal KNbO3 at room temperature, obtained that the direction of the local Nb atom off-center displacement agrees closely with the direction of the [110] polar axis in the orthorhombic phase. The error analysis, however, was not performed.…”

Section: Discussioncontrasting

confidence: 99%

See 1 more Smart Citation

Pressure-induced changes in the local structure of KNbO[sub 3]

Frenkel¹,

Stern²,

Yacoby³

1998

AIP Conference Proceedings

View full text Add to dashboard Cite

The local structure of the perovskite KNbO3 at 77 K and 300 K under high pressure, up to 15.8 GPa, h~s been investigated using the X-ray absorption fine structure (XAFS) technique. We found that local distortions exist throughout the measured range which are peaked off-center at the rhombohedral symmetry sites with a width narrower than the separation between the rhombohedral and orthorhombic sites. On the other hand, diffraction indicates an orthorhombic average structure at 300K, and optical measurements suggest a transition to a cubic phase at high pressures. To explain the difference between pressure-induced changes in KNb03 structure as measured by XAFS and optical techniques, a pressure-dependent hopping rate in the framework of the eight-site model is proposed.

show abstract

Section: Discussioncontrasting

confidence: 99%

“…The quality of the fits reported in Ref. [37] indicates that the uncertainties in the obtained parameters (due to noise in the data or lack of spatial resolution) may have been too large to convincingly discriminate between the [110] and [111] directions of Nb atom disl)lacements.…”

Section: Discussionmentioning

confidence: 99%

Pressure-induced changes in the local structure of KNbO[sub 3]

Frenkel¹,

Stern²,

Yacoby³

1998

AIP Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…In addition, a more recent femtosecond time-resolved spectroscopy study for this phase rule out relaxational contributions of the same symmetry as the soft mode [10] . Also, other XAFS measurements at room temperature revealed that the direction of the Nb displacement is as close to the polar axis as the order of temperature atomic displacements [11] .…”

Section: Introductionmentioning

confidence: 80%

Dynamic mechanisms of the structural phase transitions in KNbO₃: Molecular dynamics simulations

et al. 1999

View full text Add to dashboard Cite

The question on the dominant driving mechanism (displacive or orderdisorder) at each structural phase transition of KNbO 3 is investigated by means of molecular dynamics simulations. To this purpose, we first develop a shell model by determining its potential parameters in order to reproduce the ferroelectric instabilities obtained by first-principles total energy calculations. The phase diagram as a function of temperature is obtained through constant-pressure molecular dynamics simulations. The analysis of the dynamical structure factor and the microscopic dynamics of the particles in the different phases allows us to reveal the nature of the dynamics associated with each structural transition. Correlations between local polarizations forming chain-like precursor clusters in the paraelectric phase are examined.

show abstract

“…The artifacts considerably distort the spectra and can introduce significant errors into results. In the case of Bragg reflections the problem is usually solved by applying special experimental approaches such as the oscillating of samples (Revenant-Brizard et al, 1997), adjustment of single crystal sample to avoid the presence of Bragg reflections in the wavelength region of interest (Shuvaeva et al, 1997) or by using oriented polycrystalline samples for polarized XAFS studies (Yang et al, 1988). However, these methods require special experimental equipment or sample preparation techniques and are not applicable in some cases.…”

Section: Introductionmentioning

confidence: 99%

Deglitching procedure for XAFS

Zhuchkov¹,

Shuvaeva²,

Yagi³

et al. 2001

J Synchrotron Radiat

Self Cite

View full text Add to dashboard Cite

A computer program for eliminating artifacts such as glitches and Bragg peaks of the polarized XAFS spectra is presented. It permits to easily locate and to eliminate from the EXAFS spectra the additional signals originated from the Bragg scattering by crystalline samples. The test of the procedure on the spectra with specially introduced artifacts and on the experimental polarized XAFS spectra showed its high effectiveness.

show abstract

Polarized XAFS Study of KNbO₃Local Structure

Cited by 6 publications

References 14 publications

Pressure-induced changes in the local structure of KNbO[sub 3]

Pressure-induced changes in the local structure of KNbO[sub 3]

Dynamic mechanisms of the structural phase transitions in KNbO₃: Molecular dynamics simulations

Deglitching procedure for XAFS

Contact Info

Product

Resources

About

Polarized XAFS Study of KNbO3Local Structure

Cited by 6 publications

References 14 publications

Pressure-induced changes in the local structure of KNbO[sub 3]

Pressure-induced changes in the local structure of KNbO[sub 3]

Dynamic mechanisms of the structural phase transitions in KNbO3: Molecular dynamics simulations

Deglitching procedure for XAFS

Contact Info

Product

Resources

About

Polarized XAFS Study of KNbO₃Local Structure

Dynamic mechanisms of the structural phase transitions in KNbO₃: Molecular dynamics simulations