Systematic Raman study of Tl/sub 2/Ca/sub n//sub -1/Ba/sub 2/ Cu/sub n/O/sub 4+2//sub n/ (n = 1,2,3) high-temperature superconductors

Journal Article · Thu Dec 01 04:00:00 EST 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.11962· OSTI ID:6601438

Krantz, M; Rosen, H J; Macfarlane, R M; Lee, V Y

We report the results of Raman measurements performed on polycrystalline samples of superconducting Tl/sub 2/Ca/sub n//sub -1/Ba/sub 2/Cu/sub n/O/sub 4+2//sub n/ (n = 1,2,3) with well-characterized transport, magnetic, and structural properties. The room-temperature first-order Raman spectra of polycrystalline samples of predominantly Tl/sub 2/Ba/sub 2/CuO/sub 6/, Tl/sub 2/CaBa/sub 2/Cu/sub 2/O/sub 8/, and Tl/sub 2/Ca/sub 2/Ba/sub 2/Cu/sub 3/O/sub 10/ phases, with respective superconducting transition temperatures of 10, 110, and 125 K display a systematic variation with the number of CuO/sub 2/ layers and great similarities with the Raman spectrum of YBa/sub 2/Cu/sub 3/O/sub 7/. Comparison with Raman spectra of the impurity phase candidates BaCO/sub 3/, BaO/sub 2/, BaCuO/sub 2/, CaCuO/sub 2/, Tl/sub 2/O/sub 3/, and TlCa/sub 5/Cu/sub 6/O/sub x/ allows identification of intrinsic Raman modes of the superconducting phases. Factor group analysis of the three body-centered tetragonal structures space group 14/mmm, yields the mode classifications and the atoms involved in the modes of A/sub 1//sub g/ and B/sub 1//sub g/ symmetry corresponding to c-axis motion that produce the strongest modulation of the polarizability. The systematic variation between the spectra of the three phases and comparison with the well-characterized YBa/sub 2/Cu/sub 5/O/sub x/ Raman spectrum suggests mode assignments for the high-frequency modes of A/sub 1//sub g/ and B/sub 1//sub g/ symmetry involving oxygen motion.

• Research Organization: IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099
• OSTI ID: 6601438
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:16; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
DATA
EXPERIMENTAL DATA
INFORMATION
LASER SPECTROSCOPY
LATTICE VIBRATIONS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
POLYCRYSTALS
RAMAN SPECTROSCOPY
RARE EARTH COMPOUNDS
SPECTROSCOPY
SUPERCONDUCTORS
THULIUM COMPOUNDS
THULIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS