Magnetic relaxation effects in zero field cooled Y-Ba-Cu-O

This paper reports on results of the magnetic relaxation in 1:2:3 superconductors initiated by a very slow field reversal. The authors find that the relaxation at earlier times follows a stretched exponential type function, while at longer times it has a logarithmic behavior. The onset time of lnt behavior depends on the applied field. The data is interpreted in terms of a two-stage relaxation process