The influence of columnar defects on the critical current density in (Bi,Pb)2Sr2Ca2Cu3O10 + δAg tapes

An excellent tool to enhance the critical current density in superconductors is the controlled introduction of defects by irradiation damage. Irradiation with 2.65 GeV Au ions provides the generation of amorphous line defects. Polycrystalline (Bi, Pb)₂Sr₂Ca₂Cu₃O_{10 + δ} Ag tapes processed by the powder-in-tube technique were irradiated up to doses of 3.5× 10¹¹ Au ions/cm² at a temperature of 100 K. On the one hand, our irradiation experiments were performed to investigate the degree ofj _c enhancement and, on the other hand, to examine the flux pinning mechanism in (Bi, Pb)₂Sr₂Ca₂Cu₃O_{10 + δ} tapes. Characterization of the samples was performed by magnetization measurements using a vibrating sample magnetometer (VSM) up to 13 T in a temperature range between 5 and 100 K. Further, we have measured the relaxation of the magnetic moment before and after irradiation to determine the influence of columnar defects on the activation energyU. A comparison of the irradiation-induced effects with previous results obtained on Bi₂Sr₂CaCu₂O_{8 + δ} irradiation experiments is included.