Magnetoresistance of c-axis-oriented epitaxial YBa2Cu3O7−x films above Tc

Abstract

Magnetoresistance in high-quality single-crystal films of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathrm{x}}$ studied in a temperature range $T_c$≲T≲210 K is presented for magnetic field configurations both parallel and perpendicular to the conducting ab plane. The data are analyzed in terms of recent theories of superconducting fluctuations considering both orbital and Zeeman effects in Aslamazov-Larkin and Maki-Thompson terms. From the analysis, the phase-breaking time of carriers is determined to be ${\tau }_{\rho }$=(1±0.1)×${10}^{\mathrm{-}13}$ sec at 100 K with a T dependence of 1/${\tau }_{\rho }$∝$T^{1\mathrm{-}2}$. ${\xi }_c$(0)=1.5±0.5 Å and ${\xi }_{\mathrm{ab}}$(0) =11.5±0.5 Å are also derived for the inter- and intralayer coherence lengths.