Phonon characterization of Bi2 (Sr1-xCax)2 CuO6+δ by infrared and Raman spectroscopy

Popović, Zdenka; Thomsen, C.; Cardona, M.; Liu, R.; Stanišić, G.; Kremer, Reinhard K.; König, W.

doi:10.1016/0038-1098(88)90547-9

Cited by 75 publications

(21 citation statements)

References 7 publications

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“…Since only the strongest infrared modes of SBT are reported here, complementarity makes it unlikely that the Raman lines seen at 607 and 812 cm Ϫ1 arise from the similar-frequency TO and LO modes found in Tables II and III. Comparisons to some simpler oxides can be made, as is sometimes attempted for phonons in the similarly complex bismuth-based cuprate superconductors. 33 Bi 2 O 3 presents a dense spectrum of infrared and Raman lines from 540 cm Ϫ1 downward, including infrared bands 33 at 38 and 58 cm Ϫ1 ͑below our infrared range of measurement͒ and Raman bands 34 near 60 cm Ϫ1 . It is likely that bismuth displacements play a major role in the eigenvectors corresponding to the two low-frequency Raman lines listed in Table III.…”

Section: Inventory Of Infrared and Raman Frequenciesmentioning

confidence: 99%

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
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Experimental studies were carried out on infrared-active phonons in the Aurivillius ferroelectric SrBi 2 Ta 2 O 9 ͑SBT͒, using reflectivity measurements ͑down to 200 cm Ϫ1 ͒ and transmission measurements ͑down to 100 cm Ϫ1 ͒ on crystals, pellets, and thin films. An analysis was done of the contrasting consequences of the competing orthorhombic and pseudotetragonal symmetries in SBT. Reflectivity results for light polarized in the ab plane show that the anisotropy in this plane is small in the frequency range from 300 to 1200 cm Ϫ1 , indicating the influence of the approximate tetragonal symmetry. Dielectric dispersion properties were derived for this polarization (EЌc) in this frequency range. The transverse-optical ͑TO͒ and longitudinal-optical ͑LO͒ frequencies corresponding to the dominant EЌc band are 613 and 773 cm Ϫ1 , respectively. This strong, highfrequency band arises from a mode dominated by the motion of the oxygen sublattice; its TO and LO frequencies yield an oxygen-ion Szigeti effective charge of Ϫ1.5e. Frequency estimates for the TO ͑LO͒ pairs of other strong bands are 188͑330͒ and 334(451) cm Ϫ1 for EЌc, and 610͑675͒ and 780(815) cm Ϫ1 for Eʈc. In addition to the main infrared bands, the main Raman bands of SBT are also reported.

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Section: Inventory Of Infrared and Raman Frequenciesmentioning

confidence: 99%

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
View full text Add to dashboard Cite

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“…Several groups [7][8][9][10][11][12][13] have reported results of infrared (IR) spectroscopic studies of powder as well as singlecrystal specimens of CuO. The interpretation of infrared spectra was always embarrassed by the low crystal symmetry, especially for the case of polycrystalline samples.…”

Section: Introductionmentioning

confidence: 99%

Infrared spectroscopic study of CuO: Signatures of strong spin-phonon interaction and structural distortion

et al. 2001

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Optical properties of single-crystal monoclinic CuO in the range 70 -6000 cm −1 were studied at temperatures from 7 to 300 K. Normal reflection spectra were obtained from the (001) and (010) crystal faces thus giving for the first time separate data for the Au and Bu phonon modes excited in the purely transverse way (TO modes). Mode parameters, including polarizations of the Bu modes not determined by the crystal symmetry, were extracted by the dispersion analysis of reflectivity curves as a function of temperature. Spectra of all the components of the optical conductivity tensor were obtained using the Kramers-Kronig method recently extended to the case of the low-symmetry crystals. The number of strong phonon modes is in agreement with the factor-group analysis for the crystal structure, currently accepted for the CuO. However, several "extra" modes of minor intensity are detected; some of them are observed in the whole studied temperature range, while existence of others becomes evident at low temperatures. Comparison of frequencies of "extra" modes with the available phonon dispersion curves points to possible "diagonal" doubling of the unit cell {a, b, c} → {a+c, b, a-c} and formation of the superlattice. The previously reported softening of the A 3 u mode (∼ 400 cm −1 ) with cooling at TN is found to be ∼ 10 % for the TO mode. The mode is very broad at high temperatures and strongly narrows in the AFM phase. We attribute this effect to strong resonance coupling of this mode to optical or acoustic bi-magnons and reconstruction of the magnetic excitations spectrum at the Néel point. A significant anisotropy of ǫ ∞ is observed: it was found to be 5.9 along the b-axis, 6.2 along the [101] chains and 7.8 the [101] chains. The "transverse" effective charge is more or less isotropic; its value is about 2 electrons.

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“…The measurements done on these materials probed primarily the ab-properties, [6][7][8][9] or polycrystalline samples were used. [10][11][12][13][14] The unambiguous information on the IR caxis phonon spectra were obtained on Bi 2 Sr 2 CaCu 2 O 8 (Bi2212) single crystals 15,16 and on Tl 2 Ba 2 Ca 2 Cu 3 O 10 (Tl2223) film. 17 Extensive studies, along with the efforts to assign the main oxygen modes in these compounds were also performed using Raman scattering.…”

Section: Introductionmentioning

confidence: 99%

Systematics ofc-axis phonons in the thallium- and bismuth-based cuprate superconductors

et al. 1999

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We present grazing incidence reflectivity measurements in the far infrared region at temperatures above and below Tc for a series of thallium (Tl2Ba2CuO6, Tl2Ba2CaCu2O8) and bismuth (Bi2Sr2CuO6, Bi2Sr2CaCu2O8, and Bi2−xPbxSr2CaCu2O8) based cuprate superconductors. From the spectra, which are dominated by the c-axis phonons, longitudinal frequencies (LO) are directly obtained. The reflectivity curves are well fitted by a series of Lorentz oscillators. In this way the transverse (TO) phonon frequencies were accurately determined. On the basis of the comparative study of the Bi and Tl based cuprates with different number of CuO2 layers per unit cell, we suggest modifications of the assignment of the main oxygen modes. We compare the LO frequencies in Bi2Sr2CaCu2O8 and Tl2Ba2Ca2Cu3O10 obtained from intrinsic Josephson junction characteristics with our measurements, and explain the discrepancy in LO frequencies obtained by the two different methods.

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Phonon characterization of Bi2 (Sr1-xCax)2 CuO6+δ by infrared and Raman spectroscopy

Cited by 75 publications

References 7 publications

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
View full text Add to dashboard Cite

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
View full text Add to dashboard Cite

Infrared spectroscopic study of CuO: Signatures of strong spin-phonon interaction and structural distortion

Systematics ofc-axis phonons in the thallium- and bismuth-based cuprate superconductors

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Phonon characterization of Bi2 (Sr1-xCax)2 CuO6+δ by infrared and Raman spectroscopy

Cited by 75 publications

References 7 publications

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2OMoret1, Zallen2, Newnham3 et al. 1998Phys. Rev. B606290View full textAdd to dashboardCite

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2OMoret1, Zallen2, Newnham3 et al. 1998Phys. Rev. B606290View full textAdd to dashboardCite

Infrared spectroscopic study of CuO: Signatures of strong spin-phonon interaction and structural distortion

Systematics ofc-axis phonons in the thallium- and bismuth-based cuprate superconductors

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Product

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About

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
View full text Add to dashboard Cite

Infrared activity in the Aurivillius layered ferroelectricSrBi2Ta2O
Moret
¹
,
Zallen
²
,
Newnham
³

et al. 1998
Phys. Rev. B
60
6
29
0
View full text Add to dashboard Cite