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Thermal Transport in 90 K‐ and 60 K‐Phase YBa 2 Cu 3 O 7—δ High‐T c Oxides
Author(s) -
Ikebe M.,
Fujishiro H.,
Nakasato K.,
Mikami T.,
Naito T.,
Fukase T.
Publication year - 1998
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(199810)209:2<413::aid-pssb413>3.0.co;2-4
Subject(s) - condensed matter physics , superconductivity , phonon , phase (matter) , anisotropy , scattering , thermal diffusivity , materials science , thermal conductivity , phonon scattering , electrical resistivity and conductivity , chemistry , physics , thermodynamics , optics , composite material , organic chemistry , quantum mechanics
The thermal diffusivity α and conductivity κ of YBa 2 Cu 3 O 7—δ sintered crystals with oxygen deficiencies δ ≈ 0.10 (90 K‐phase) and δ ≈ 0.35 (60 K‐phase) have been quasi‐simultaneously measured between 15 and 170 K. The phonon and electron components of α and κ are separated and analyzed from viewpoints of both the d‐ and s‐wave superconducting energy gap models. It is found that the enhancement of κ below T c , which is commonly observed for 90 K‐ and 60 K‐phase YBa 2 Cu 3 O 7—δ , is consistent only with the phonon origin model under d‐wave energy gap anisotropy with the maximum gap 2Δ max / k B T c ≈ 5. The phonon scattering mechanisms are synthetically analyzed for both 90 K‐ and 60 K‐phase YBa 2 Cu 3 O 7—δ and the oxygen vacancy is found to be one of the dominant phonon scattering centers in this system.