Universality of glass scaling in a YBa${}_2$Cu${}_3$O${}_{7-\delta }$ thin film

Abstract

The universal behavior of the continuous superconducting (glass) phase transition is studied in a YBa${}_2$Cu${}_3$O${}_{7-\delta }$ thin film. A new analysis technique for extracting critical exponents is developed, using current-voltage ($J$-$E$) measurements. The method places narrow limits on the glass scaling exponents, $z_g$ and ${\nu }_g$, as well as the glass transition temperature, $T_g(H)$. The universal values $z_g=3.8\pm 0.2$ and ${\nu }_g=1.8\pm 0.1$ are obtained. Using these values, the data are scaled for fields in the range 1-9~T. Collapse of the scaling forms at different fields describes the universal scaling function. The field dependence of the universal collapse is interpreted in terms of the 3D~XY multicritical scaling theory.

6 pages LaTeX, 4 figures provided upon request