Raman-scattering results from Y1-xCaxSr2Cu2GaO7

D. Salamon, R. Liu, M. V. Klein, D. A. Groenke, Kenneth R Poeppelmeier, B. Dabrowski, P. D. Han, D. A. Payne

Research output: Contribution to journalArticle

4 Citations (Scopus)

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 languageEnglish
Pages (from-to)12242-12247
Number of pages6
JournalPhysical Review B
Volume47
Issue number18
DOIs
Publication statusPublished - 1993

    Fingerprint

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Salamon, D., Liu, R., Klein, M. V., Groenke, D. A., Poeppelmeier, K. R., Dabrowski, B., Han, P. D., & Payne, D. A. (1993). Raman-scattering results from Y1-xCaxSr2Cu2GaO7. Physical Review B, 47(18), 12242-12247. https://doi.org/10.1103/PhysRevB.47.12242