Normal-state transport parameters of epitaxial thin films ofYBa2Cu3O7−δ

Abstract

We report on a striking correlation in the electrical transport behavior of very high-quality ($j_c\sim 3.4\times {10}^6$ A/${\mathrm{cm}}^2$ at $T=77\mathrm{}$ K) epitaxial thin films of high-$T_c$ Y-Ba-Cu-O in the normal state. With increasing superconducting performance, as characterized by the transition temperature, transition-temperature width, and critical current density, the resistivity $\rho$, and the Hall coefficient $R_H$, both assume remarkably simple temperature dependences $\rho =\alpha T$ and $R_H^{}{}_{}{}^{-1\mathrm{}}=\beta T$ leading to a Hall mobility ${\mu }_H\propto T^{-2\mathrm{}}$. The magnetoresistance at 10 T is less than $\left|\frac{\Delta \rho }{\rho }\right|<\mathrm{}{10}^{-3\mathrm{}}$. We discuss an extreme two-carrier model to assess the $T$ dependence of $R_H$.