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Raman Scattering Studies of the Carbon Atom Vibrations in Superconducting Rare‐Earth Carbide Halides RE 2 C 2 (X,X′) 2 (RE = Y, Gd; X, X′ = Br, I)
Author(s) -
Henn R. W.,
Strach T.,
Kremer K.,
Simon A.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199909)215:1<513::aid-pssb513>3.0.co;2-w
Subject(s) - raman spectroscopy , superconductivity , phonon , raman scattering , atom (system on chip) , carbon fibers , materials science , halogen , crystallography , carbide , analytical chemistry (journal) , chemistry , atomic physics , condensed matter physics , physics , optics , metallurgy , organic chemistry , alkyl , composite number , computer science , composite material , embedded system
The Raman spectra of the layered superconductors RE 2 C 2 (X,X′) 2 (RE = Y, Gd; X, X′ = Br, I) were measured on single‐crystal and polycrystalline specimens using a micro‐Raman technique. Low energy modes (ω < 300 cm —1 ) correspond to mixed vibrations of rare‐earth and halogen atom sublattices. Two high energy modes at ≈ 400 and ≈ 1600 cm m1 ) can be assigned to the tilting and stretching vibrations of the carbon C 2 units. These carbon‐related phonons were identified by analyzing the isotope shifts of the Raman lines in samples in which the natural carbon was replaced by isotope‐enriched 13 C. The energy of the stretching vibration is independent of the particular host compound while the energy of the tilting vibration correlates with the size of the rare‐earth atom cage that surrounds the carbon atoms.