SUPERCONDUCTIVITY AND THERMOELECTRIC-POWER OF PR1.85CE0.15CUO4-Y

We have prepared Ce4+-doped Pr2CuO4 (Pr1.85Ce0.15CuO4-y) samples with different oxygen contents by annealing at various temperatures under argon atmosphere. Measurements of resistance and thermoelectric power of these samples reveal that there exists a correlation between the superconducting transition and the thermoelectric properties in this new copper oxide compound. The most striking finding is that the thermopowers of superconducting samples have positive values in strong contrast to the negative thermopowers of nonsuperconducting samples. This result is contrary to our naive expectation that the thermopowers of these materials will be negative in view of the negative Hall coefficients. The physical implications of our result are discussed. © 1990 The American Physical Society.