Thermoelectric power of some high-Tcoxides

Thermoelectric power (S) measurements are reported in some ${\mathrm{La}}_2$ ${\mathrm{CuO}}_{4\mathrm{-}\mathrm{y}}$ oxides with Ba and Sr doping. S gradually decreases with increasing dopant concentration x, and for small concentration the trend can be described by assuming strong correlations. While S is small for high x, the temperature dependences found indicate that the materials are not simple, uncorrelated wide-band metals.