The remanent magnetic flux creep in ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\mathrm{\ensuremath{\delta}}\mathrm{}}$ thin films was investigated in the vicinity of the critical temperature ${T}_{c}.$ The trapped magnetic flux was generated in the specimen by ramping the applied field to a finite value and then back to zero. The remanent magnetic field of persistent currents circulating in the sample was measured as a function of temperature and time. Data on the critical current density ${j}_{c}$ and the creep activation energy U were extracted. A sharp decrease of U at temperatures ${T}_{c}\ensuremath{-}T\ensuremath{\lesssim}1 \mathrm{K}$ was related to critical fluctuations. In this critical region a power-law time decay of the currents $j\ensuremath{\propto}{t}^{\ensuremath{-}p}$ was observed and explained by the logarithmic dependence ${U=U}_{0}\mathrm{ln}{(j}_{c}/j)$ for the current-assisted thermal unbinding of vortex-antivortex pairs generated by the critical fluctuations. In the critical region, the temperature dependence ${j}_{c}\ensuremath{\propto}{(T}_{c}\ensuremath{-}{T)}^{2}$ was observed. A possibility to relate this result to the critical behavior of the three-dimensional $\mathrm{XY}$ model is discussed.

The remanent magnetic flux creep in YBa2Cu3O7-delta thin films was investigated in the vicinity of the critical temperature T-c. The trapped magnetic flux was generated in the specimen by ramping the applied field to a finite value and then back to zero. The remanent magnetic field of persistent currents circulating in the sample was measured asa function of temperature and time. Data on the critical current density j(c) and the creep activation energy U were extracted. A sharp decrease of U at temperatures T-c - T less than or similar to 1 K was related to critical fluctuations. In this critical region a power-law time decay of the currents j proportional to t(-p) was observed and explained by the logarithmic dependence U = U(0)l(j(c)/j) for the current-assisted thermal unbinding of vortex-antivortex pairs generated by the critical fluctuations. In the critical region, the temperature dependence j(c)proportional to(T-c - T)(2) was observed. A possibility to relate this result to the critical behavior of the three-dimensional XY model is discussed. [S0163-1829(98)07545-6].