Abstract
We present a Raman-scattering study of Y1-xCaxSr2Cu2GaO7 for both the x=0 parent compound and doped compositions with x=0.25 and x=0.40. Extrapolation from YBa2Cu3O7-d and other cuprates allows us to assign many of the Raman-active phonon modes in the x=0 material, as well as identify a two-magnon scattering peak, a second-order phonon scattering peak, and a Raman continuum out to 4000 cm-1. Despite compositional inhomogeneities, the doped superconducting samples show some of the same low-energy phonon features as the x=0 material. There is, however, a doping-dependent shift in the positions of features in the 500-700 cm-1 range, possibly due to Ca locating on Sr sites instead of Y sites. The relative intensities of the phonon peaks in the doped material are also changed from the insulator (x=0), suggesting that a resonant Raman phenomenon is occurring. The temperature-dependent spectra show what appears to be a superconducting dip in the background intensity, but the low superconducting fractions in these samples make this difficult to verify. The doped material also has a Raman continuum out to 4000 cm-1 just as in the x=0 samples, but with the two-magnon and second-order phonon scattering peaks significantly reduced in intensity. This may be a result of changes in the long-range ordering, or another manifestation of the same resonance phenomena occurring at lower energies. Single-crystal samples of the doped material Y1-xCaxSr2Cu2GaO7 are necessary for a more conclusive Raman study.
| Original language | English |
|---|---|
| Pages (from-to) | 12242-12247 |
| Number of pages | 6 |
| Journal | Physical Review B |
| Volume | 47 |
| Issue number | 18 |
| DOIs | |
| Publication status | Published - 1993 |
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- Condensed Matter Physics
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Raman-scattering results from Y1-xCaxSr2Cu2GaO7. / Salamon, D.; Liu, R.; Klein, M. V.; Groenke, D. A.; Poeppelmeier, Kenneth R; Dabrowski, B.; Han, P. D.; Payne, D. A.
In: Physical Review B, Vol. 47, No. 18, 1993, p. 12242-12247.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Raman-scattering results from Y1-xCaxSr2Cu2GaO7
AU - Salamon, D.
AU - Liu, R.
AU - Klein, M. V.
AU - Groenke, D. A.
AU - Poeppelmeier, Kenneth R
AU - Dabrowski, B.
AU - Han, P. D.
AU - Payne, D. A.
PY - 1993
Y1 - 1993
N2 - We present a Raman-scattering study of Y1-xCaxSr2Cu2GaO7 for both the x=0 parent compound and doped compositions with x=0.25 and x=0.40. Extrapolation from YBa2Cu3O7-d and other cuprates allows us to assign many of the Raman-active phonon modes in the x=0 material, as well as identify a two-magnon scattering peak, a second-order phonon scattering peak, and a Raman continuum out to 4000 cm-1. Despite compositional inhomogeneities, the doped superconducting samples show some of the same low-energy phonon features as the x=0 material. There is, however, a doping-dependent shift in the positions of features in the 500-700 cm-1 range, possibly due to Ca locating on Sr sites instead of Y sites. The relative intensities of the phonon peaks in the doped material are also changed from the insulator (x=0), suggesting that a resonant Raman phenomenon is occurring. The temperature-dependent spectra show what appears to be a superconducting dip in the background intensity, but the low superconducting fractions in these samples make this difficult to verify. The doped material also has a Raman continuum out to 4000 cm-1 just as in the x=0 samples, but with the two-magnon and second-order phonon scattering peaks significantly reduced in intensity. This may be a result of changes in the long-range ordering, or another manifestation of the same resonance phenomena occurring at lower energies. Single-crystal samples of the doped material Y1-xCaxSr2Cu2GaO7 are necessary for a more conclusive Raman study.
AB - We present a Raman-scattering study of Y1-xCaxSr2Cu2GaO7 for both the x=0 parent compound and doped compositions with x=0.25 and x=0.40. Extrapolation from YBa2Cu3O7-d and other cuprates allows us to assign many of the Raman-active phonon modes in the x=0 material, as well as identify a two-magnon scattering peak, a second-order phonon scattering peak, and a Raman continuum out to 4000 cm-1. Despite compositional inhomogeneities, the doped superconducting samples show some of the same low-energy phonon features as the x=0 material. There is, however, a doping-dependent shift in the positions of features in the 500-700 cm-1 range, possibly due to Ca locating on Sr sites instead of Y sites. The relative intensities of the phonon peaks in the doped material are also changed from the insulator (x=0), suggesting that a resonant Raman phenomenon is occurring. The temperature-dependent spectra show what appears to be a superconducting dip in the background intensity, but the low superconducting fractions in these samples make this difficult to verify. The doped material also has a Raman continuum out to 4000 cm-1 just as in the x=0 samples, but with the two-magnon and second-order phonon scattering peaks significantly reduced in intensity. This may be a result of changes in the long-range ordering, or another manifestation of the same resonance phenomena occurring at lower energies. Single-crystal samples of the doped material Y1-xCaxSr2Cu2GaO7 are necessary for a more conclusive Raman study.
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U2 - 10.1103/PhysRevB.47.12242
DO - 10.1103/PhysRevB.47.12242
M3 - Article
VL - 47
SP - 12242
EP - 12247
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 18
ER -