TY - JOUR
T1 - Specific heat study of the Na0.3CoO2 · 1.3H2O superconductor
T2 - Influence of the complex chemistry
AU - Ueland, B. G.
AU - Schiffer, P.
AU - Schaak, R. E.
AU - Foo, M. L.
AU - Miller, V. L.
AU - Cava, R. J.
N1 - Funding Information:
We gratefully acknowledge support from NSF grants DMR-0244254, DMR-0101318, DMR-0213706 and DOE grant DE-FG02-98-ER45706.
PY - 2004/2/1
Y1 - 2004/2/1
N2 - We report results of specific heat measurements on polycrystalline samples of the layered superconductor, Na0.3CoO2 · 1.3H2O. The electronic contribution to the specific heat, γ, is found to be 12.2 mJ/mol K2. The feature at the superconducting transition is rather sharp, becoming broad and strongly suppressed in an applied magnetic field. The data indicate a residual normal state electronic specific heat at low temperatures, implying that there is a sizable population of normal state electrons in the samples even below Tc. Inhomogeneity in the Na content, to which the superconducting state is exquisitely sensitive, appears to be the most likely explanation for these results. These results further indicate that special sample handling is required for an accurate characterization of the superconducting state in this material.
AB - We report results of specific heat measurements on polycrystalline samples of the layered superconductor, Na0.3CoO2 · 1.3H2O. The electronic contribution to the specific heat, γ, is found to be 12.2 mJ/mol K2. The feature at the superconducting transition is rather sharp, becoming broad and strongly suppressed in an applied magnetic field. The data indicate a residual normal state electronic specific heat at low temperatures, implying that there is a sizable population of normal state electrons in the samples even below Tc. Inhomogeneity in the Na content, to which the superconducting state is exquisitely sensitive, appears to be the most likely explanation for these results. These results further indicate that special sample handling is required for an accurate characterization of the superconducting state in this material.
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U2 - 10.1016/j.physc.2003.08.005
DO - 10.1016/j.physc.2003.08.005
M3 - Article
AN - SCOPUS:0346970752
SN - 0921-4534
VL - 402
SP - 27
EP - 30
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
IS - 1-2
ER -