Vortex line pinning and Bose-glass dynamics in heavy-ion irradiated Bi2Sr2CaCu2O8+δ single crystals

The angular dependence of the ac screening of Bi2Sr2CaCu2O8+δ single crystals irradiated with 5.8 GeV Pb ions is used to demonstrate the importance of interactions between vortex segments in different CuO2 layers. The field tilt angle below which pinning by the columnar defects is effective is very large: Θa70°. The magnitude and frequency dependence of the shielding current as well as the frequency dependence of the irreversibility line are self-consistently described by the Bose-glass theory. The irreversibility line is shown to be determined by the flux creep rate.