Short time flux creep in Bi2Sr2Ca2Cu3O10 tapes

We report magnetic relaxation, measured on a Bi2Sr2Ca2Cu3O10 tape, of a field step (50 G) superimposed on a static field of 0 - 0.2 T in a time window of 0.1 - 3600 s. The relaxation curves show a unique behaviour at the ''vortex glass transition'' (T-G(B)) determined on the same tape by transport V-I measurements. We observe a downward and an upward curvature in M(lnt) below and above TG(B), respectively. A characteristic time, where the curvature in M(lnt) starts to appear, shows a ''diverging'' behaviour as a function of temperature at TG(B). This characteristic lime apparently corresponds to a full penetration time and a crossover from logarithmic to exponential relaxation behaviour, below and above TG(B) respectively.