Magnetic relaxation of YBa2Cu3O7-delta ceramics in an intergrain-ordered phase

Magnetic relaxation is studied in YBa2Cu3O7-delta ceramics consisting of we akly coupled submicron grains. In the system, the ordering proceeds success ively from the intragrain ordered state to the intergrain one at zero field . Below the intergrain ordering point T-c2, the time decay of thermoremanen t magnetization could be well fitted to a stretched exponential function. W aiting time dependence of the time decay is noticed below T-c2, suggesting a glassy phase below T-c2, in the present system. (C) 2000 Elsevier Science B.V. All rights reserved.