The Energy Gap in Bi2–xPbxSr2Ca2Cu3Oy Superconductors with x (0.00≤x ≤0.50)

A. Sedky ； A. M. Ahmed

《Chinese Journal of Physics》 41卷5期 (2003/10) Pp. 511-518

並列摘要

Thermoelectric power (TEP) measurements were made on Bi2–xPbxSr2Ca2Cu3Oy samples with various values of x (0.00≤x≤0.50). It was found that the measured TEP values fit reasonably well with the values deduced from the two-band model. The energy gap Eg as a function of both the Pb content (x) and the temperature was calculated for all samples and are summarized as follows: Eg is zero for all samples at temperature T0 determined from the minimum of dS/dT against T; Eg is negative at T＞T0 for the x≤0.20 samples and becomes positive at T＜T0; Eg is positive at T＞T0 for the x＞0.20 samples and becomes negative at T ＜ T0 The activation energy Ea, the hole density n, and the hole concentration per Cu ion H are also calculated and discussed for all samples.