Infrared-absorption characteristics of the pyrochlore structure*

McCauley, Ronald A.

doi:10.1364/josa.63.000721

Cited by 65 publications

(31 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The change in composition from (A 4 X 8 ) to (A 4 X 7 ) means that the structure of the compound may correspond either to defect-disordered fluorite (cubic space group Fm3m-O 5 h ), defect-ordered pyrochlore (cubic space group Fd3m-O 7 h ), or to a random mixture of fluorite and pyrochlore [1,2]. The correlation between pyrochlore and neighboring structure (fluorite, perovskite) gives evidence for predisposition of the pyrochlore structure to random frustrations and disorder.…”

Section: Introductionmentioning

confidence: 99%

Relaxor-like behavior of bismuth-based pyrochlores containing Sn

Yao

Wang

2007

J Electroceram

View full text Add to dashboard Cite

Dielectric relaxation studies have been made in pyrochlore (Bi 1.5 Zn 0.5 )(Zn 0.5−x/3 Sn x Nb 1.5−2x/3 )O 7 ceramics where 0≤x≤1.5. The measurements of dielectric constant (e) and dielectric loss (tanδ) are made in the frequency range from 1 to 1,000 kHz at low temperatures from 100 to 450K. Frequency dispersion associated with dielectric relaxation phenomena in polycrystalline cubic pyrochlore is analyzed. The effect of Sn on the dielectric relaxation behavior and the physical mechanism giving polarization is briefly discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Relaxor-like behavior of bismuth-based pyrochlores containing Sn

Yao

Wang

2007

J Electroceram

View full text Add to dashboard Cite

show abstract

“…A factor group analysis of the ideal pyrochlore structure yields six Raman-active modes ͑R͒, seven IR modes, and one F 1u acoustic mode 38 FIG. 2.…”

mentioning

confidence: 99%

Raman study of phonon modes in bismuth pyrochlores

et al. 2010

View full text Add to dashboard Cite

have been measured at room temperature. The frequencies of the Raman modes, obtained from first-principles calculations, for Bi 2 Ti 2 O 7 are presented for comparison. The spectra of the four samples are similar and agree well with the first-principles calculations. Each bismuth pyrochlore shows more than the six modes expected for the ideal pyrochlore structure. The analysis shows that many of the additional modes could be explained as the relaxation of the selection rules due to the displacive disorder. The Raman modes are assigned by reference to spectra of other pyrochlore materials, comparison to infrared data, and the ab initio calculations.

show abstract

“…This indicates that other absorption mechanism is operative, which may be attributed to the enrichment of the interaction and cooperation between each ion and the optical absorption transition of 4f electrons, together with the increase of lattice defects due to the doping of TiO 2 . At low wavelengths, no intense vibration absorption peaks are detected except that of H 2 O, Wang et al [12] [17,18]. Fig.…”

Section: Radiation Mechanismsmentioning

confidence: 96%

“…While, the vibration frequency is also determined by the mass and bonding strength of the atomic species in the molecular or atomic group. The bonding strength of two atoms depends mainly on the interatomic spacing between them [17]. Factor group analysis of A 2 B 2 O 7 pyrochlore has predicted the appearance of seven infraredactive modes (IR) for the vibration spectra [12].…”

Section: Radiation Mechanismsmentioning

confidence: 99%