Pinning by columnar defects in irradiated YBa2Cu3O7 (YBCO) and Bi2SrCa
Cu2O8 (BSCCO) crystals is most efficient when the field is parallel to
the defect. However, in the low field limit the remanent magnetizatio
n is independent of the direction of the field, indicating that the fl
uxons flop towards the columnar defect. The flux-flop is almost temper
ature independent in YBCO and strongly temperature dependent in BSCCO
due to the different nature of the vortices.