Single crystals of Bi2Sr2CaCu2O8+δ (Tc84 K) have been exposed to irradiation with 0.5-GeV I127 ions with various fluences perpendicular to the sample surface and hence parallel to the c axis. This kind of projectile produces columnar defects in the superconductors. By use of the high-resolution Faraday-effect (HRF) technique, domain patterns of the Shubnikov phase are obtained. From the measured flux-density profiles, the acting local pinning forces are determined. To allow direct comparison of the irradiation effects at the same experimental conditions, one-half of all crystals was covered by an absorber during the irradiation. We report fluence-dependent measurements of the pinning forces and the influence of irradiation on flux-creep effects.
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