The temperature dependence of the thermoelectric powers of the high-temperature oxide superconductors ${\mathrm{Y}}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ and ${(\mathrm{E}\mathrm{u}-\mathrm{Y})}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-x}$ is reported. The sign of the dominant carriers in the normal state is observed to be positive. Well above the superconducting transition, the magnitude of the thermoelectric power is a weakly decreasing function of temperature.

• Received 3 August 1987

DOI:https://doi.org/10.1103/PhysRevB.36.5581