Transport properties of the superconducting oxide La1.85Sr0.15CuO4

Abstract

We report electrical-resistivity, Hall-effect, and thermoelectric-power (TEP) measurements on the superconducting oxide ${\mathrm{La}}_{1.85}$ ${\mathrm{Sr}}_{0.15}$ ${\mathrm{CuO}}_4$. The transport properties indicate that in the normal state the material conducts via holes with a carrier concentration of 6.0×${10}^{21}$ ${\mathrm{cm}}^{\mathrm{-}3}$. Evidence is observed for unusual phonon-drag effects above the superconducting transition temperature $T_c$ and granular or inhomogeneous superconductivity in the vicinity of $T_c$. Below $T_c$ the resistivity, Hall constant, and TEP all drop to zero, as expected for a superconducting ground state.