Yt. Ren et al., THERMOPOWER AND RESISTIVITY MEASUREMENTS ON OXYGEN-ANNEALED HGBA2CACU2O6+DELTA, Physica. C, Superconductivity, 217(1-2), 1993, pp. 6-10
We have measured the thermoelectric power and resistivity of the 120 K
superconductor HgBa2CaCu2O6+delta (Hg-1212) as a function of temperat
ure and oxygen annealing. Before annealing the Seebeck coefficient is
moderate and positive, suggesting that the as-grown compound is slight
ly under-doped. After annealing in oxygen at 200-degrees-C for 10 h, T
(c) was enhanced by 5 K. Further annealing increased T(c) by an additi
onal 1 K and sharpened the transition. The thermopower shifts downward
with increasing doping by oxygen annealing, resembling that of the Bi
-based and Tl-based systems. The carrier concentration was estimated f
rom thermopower data and the T(c) value as approximately 0.13 and appr
oximately 0.14 per Cu before and after oxygen annealing, respectively.