Transport and Superconducting Properties on High-Tc Oxides: Pr-, Ca-Doped YBCO (124) and Quenched YBCO (123), BSCCO (2212), (2223)

Thermoelectric power are measured on high-T c oxide superconductors such as quenched YBa2Cu3O7−y (Y-(123)), Bi2Sr2CaCu2O8+y (Bi-(2212)) and Bi2Sr2Ca2Cu3 O1 0+y (Bi-(2223)), and Pr- or Ca-doped YBa2Cu 4 O8 (Y-(124)). There exists a universal relationship between T c and Seebeck coefficient (S) on the above superconductors. The T c shows its maximum at S∼ 0. The S is considered to be related with the carrier concentration which has influence upon the superconductivity. In the quenched Y-(123) and Bi-(2223), however, carrier concentration in the different type Cu-O structures (chain Cu-O and plane Cu-O without apical oxygen, respectively) is also considered to change in the higher S region.