Flux pinning potential in Bi-2223 tapes irradiated by Xe ion

We have investigated the flux pinning potential of Ag-Cu alloy sheathed Bi- 2223 tapes with columnar defects parallel to the e-axis introduced by Xe-io n irradiation. We measured the magnetic relaxation of the remanent. The sam ple was cooled in zero field and the field above H*, where the flux front p enetrated at the center of the sample. The time decay of the remanent momen t was measured for about 10(5) s. The relaxation of the remanent moment sho wed the linear In(t) dependence in all observed temperature range. The chan ge in the distribution of the activation energies with irradiation was obta ined. Since the deeper pinning center were increased, it is expected that t he columnar defects will act as effective pinning centers. (C) 2001 Elsevie r Science B.V. All rights reserved.