Vortex line pinning in Bi2Sr2CaCu2O8 single crystals with columnar defects

摘要

The ac transmittivity of heavy-ion irradiated Bi2Sr2CaCu 2O8 single crystals shows a sharp cusp as function of the dc field orientation with respect to the columnar defects. This unambiguously demonstrates the connected nature of vortices in these samples. In contrast, the irreversibility line does not reveal a cusp.