Raman scattering from triple perovskites with the Ba/sub 2/YCu/sub 3/O/sub x/ structure: Normal mode assignments from substitutions on the Ba site

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.287· OSTI ID:6441579

Stavola, M; Krol, D M; Schneemeyer, L F; Sunshine, S A; Waszczak, J V; Kosinski, S G

Raman spectra are reported for Ba/sub 1.5/La/sub 1.5/Cu/sub 3/O/sub 7//sub --//sub delta/ ceramics and Sr/sub 2/YCu/sub 3-//sub x/Al/sub x/O/sub 7-//sub delta/ ceramics and single crystals. The shifts in the frequencies of the Raman features for these triple perovskites, as compared to Ba/sub 2/YCu/sub 3/O/sub x/, provide additional evidence for the assignments of the normal modes. There are large changes in the frequency of the prominent 500-cm/sup -1/ feature that are well correlated to changes in the lengths of the axial Cu-O bonds. This correlation supports the assignment of the 500-cm/sup -1/ feature to the axial stretching of the oxygen atoms that bridge the Cu sites. The substitution of Sr for Ba does not change the frequency of the 140-cm/sup -1/ mode of Ba/sub 2/YC/sub 3/O/sub x/, thereby supporting its assignment to axial stretching of the planar Cu atoms rather than to a Ba mode. With these new data and the previous, definitive assignment of the feature at 340 cm/sup -1/, the assignments of the five prominent Raman modes are well supported by experiment and agree with lattice-dynamics calculations.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 6441579
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:1; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LATTICE VIBRATIONS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
RAMAN SPECTRA
RARE EARTH COMPOUNDS
SCATTERING
SPECTRA
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES