Dimensionality of flux pinning in (Bi,Pb)2Sr2Ca2Cu3O10+δ Ag tapes with columnar defects—Crossover from two-dimensional to three-dimensional behavior

We introduced columnar defects into (Bi,Pb)2Sr2Ca2Cu3O10+δ Ag tapes by irradiation with 2.65 GeV 197Au ions to investigate the dimensionality of pinning for this compound. Samples were irradiated up to fluences of 3.5×1011 ions/cm2 at a temperature of 100 K. The ion beam was directed both perpendicular and under a tilt angle of −60° to the tape surface. Our samples showed homogeneous columnar line defects throughout the whole thickness of the superconducting core. As a novel result we found evidence for marked deviations from two-dimensional behavior at elevated temperatures both in magnetic and in transport measurements.