EQUILIBRIUM MAGNETIZATION IN HEAVY-ION-IRRADIATED BI2SR2CACU2O8, PROBED BY TORQUE AND SQUID MAGNETOMETRY

Measurements of the magnetization and torque on heavy-ion-irradiated B i2Sr2CaCu2O8 single crystals show that the equilibrium distribution of pancake vortices only depends on the applied field component parallel to the c axis, for fields both above and below the dose equivalent fi eld and also for various irradiation angles with respect to the c axis . This observation Is in clear contrast with the irreversible magnetiz ation, which shows a. large anisotropy with respect to the field align ment with the columnar defects. [S0163-1829(98)51526-3].