PHASE DIAGRAMS OF SURFACE HEAVY ION IRRADIATED BI-2223/AG TAPES

Abstract

Surface columnar defects, SCDs, are produced in high quality (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O y / Ag tapes by irradiating them with 0.25 GeV gold ions only on a top layer up to ≈15% of the full volume. The ion beam is orthogonal to the tape plane. In this paper we report experimental results of the surface implantation of columnar defects both in the high-current and in the low-current regime with a particular emphasis on the influence of SCDs on the anisotropy dependent properties. Some characteristic labels of the SCD implantation are pointed out. A comparison between all the results in the two current regimes is made. A hint is given concerning analogous results obtained by means of transport electrical measurements. The experimental data can be interpreted by assuming that a new confined phase driven by SCDs sets up in both the current regimes. Acting on the dose, it is possible to obtain tunable control of the in-field performance in both regimes.