ONSET OF BULK PINNING IN BSCCO SINGLE-CRYSTALS

The long growth defects often found in Bi2Sr2CaC2O8 ''single'' crystal s effectively weaken the geometrical barrier and lower the field of fi rst flux penetration. This means that the intrinsic (bulk) magnetic pr operties can be more easily accessed using magnetic measurements. Thus , the onset of strong bulk flux pinning in the sample bulk is determin ed to lie at T approximate to 40 Ii; indepedent of whether the field s trength is above or below the field of the second peal in the magnetis ation.