Strong vortex pinning and anisotropy in Ag/BSCCO-2223 tapes caused by surface columnar defects

This paper is aimed at investigating the vortex dynamics driven by 0.25 GeV Au ion implantation in Ag/BSCCO-2223 tapes. Columnar defects are produced perpendicularly to the tape plane and only affect a surface layer of about 10% of the whole sample volume. The paper shows that this defect topology d oes not deteriorate the critical temperature significantly. Moreover, the i rreversibility line (LL) measured with the applied held perpendicular to th e tracks is nearly unaffected. On the contrary, the a with the applied fiel d either parallel to the tracks or moderately tilted is shifted towards hig her fields and temperatures. The amount of the shift is comparable with tha t obtained for tracks crossing the whole sample. In a large range of magnet ic fields near the dose equivalent field the IL anisotropy falls to zero. H owever, the ILs after surface implantation exhibit very peculiar features.