TY - JOUR
T1 - Thermal conductivity of YBa2Cu3O7- below 1 K
T2 - Evidence for normal-carrier transport well below Tc
AU - Cohn, J. L.
AU - Peacor, S. D.
AU - Uher, C.
PY - 1988/1/1
Y1 - 1988/1/1
N2 - We report measurements of thermal conductivity at temperatures below 1 K on superconducting and insulating (oxygen-deficient) ceramic YBa2Cu3O7-. For the superconductor, the temperature dependence of the thermal conductivity begins to weaken below 0.5 K, approaching a T-linear behavior. Below 1 K, the insulating material, produced by vacuum-annealing the superconductor, exhibits a T3 dependence characteristic of phonon boundary scattering. Reannealing samples in flowing oxygen restores superconductivity at 90 K and the T-linear behavior of the thermal conductivity at the lowest temperatures. Scanning electron micrographs reveal an identical grain structure before and after successive heat treatments, indicating that the anomaly in for the superconductor is not associated with the specific geometry of the microstructure. The data are consistent with the presence of a small number of normal carriers in the high-Tc material.
AB - We report measurements of thermal conductivity at temperatures below 1 K on superconducting and insulating (oxygen-deficient) ceramic YBa2Cu3O7-. For the superconductor, the temperature dependence of the thermal conductivity begins to weaken below 0.5 K, approaching a T-linear behavior. Below 1 K, the insulating material, produced by vacuum-annealing the superconductor, exhibits a T3 dependence characteristic of phonon boundary scattering. Reannealing samples in flowing oxygen restores superconductivity at 90 K and the T-linear behavior of the thermal conductivity at the lowest temperatures. Scanning electron micrographs reveal an identical grain structure before and after successive heat treatments, indicating that the anomaly in for the superconductor is not associated with the specific geometry of the microstructure. The data are consistent with the presence of a small number of normal carriers in the high-Tc material.
UR - http://www.scopus.com/inward/record.url?scp=0000941408&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000941408&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.38.2892
DO - 10.1103/PhysRevB.38.2892
M3 - Article
AN - SCOPUS:0000941408
VL - 38
SP - 2892
EP - 2895
JO - Physical Review B
JF - Physical Review B
SN - 0163-1829
IS - 4
ER -