Evidence for scaling invariance and universality of the irreversibility line of high temperature superconductors.

Abstract

Measurements of the irreversibility line H(${\mathit{T}}^{\mathrm{*}}$) of ${\mathrm{Y}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Pr}}_{\mathit{x}}$${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{6.97}$, a system in which the superconducting transition ${\mathit{T}}_{\mathit{c}}$ can be varied from 0 to 92 K, show that H(${\mathit{T}}^{\mathrm{*}}$) obeys a universal scaling relation characterized by an m=3/2 power law near ${\mathit{T}}_{\mathit{c}}$, with a crossover to a more rapid temperature dependence below T/${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}0.6. The applicability of the scaling formula to other high ${\mathit{T}}_{\mathit{c}}$ superconductors is tested, with the results suggesting that both the crossover phenomenon and the power law temperature dependence are ubiquitous, scale-invariant properties of high temperature superconductors.