IRREVERSIBILITY LINES AND PINNING FORCE DENSITY OF ALIGNED (BI,PB)(2)SR2CA2CU3OX SINGLE-CRYSTALS

DC Magnetic properties of aligned (Bi,Pb)(2)Sr2Ca2Cu3Ox single crystal s have been measured for the first time using SQUID magnetometer in fi eld up to 5 T and in the temperature range from 5 K to 150 K. The resu lts confirm the existence of a broad temperature and field regime with completely reversible magnetization for these crystals. The temperatu re dependence of the irreversibility field H(T) is determined from bo th M-H and M-T curves with fields oriented perpendicular to the ab pla ne of the crystal lattice. A strong field dependence of critical curre nt density has been observed in these pristine single crystals with ve ry weak pinning. These observations emphasize the importance of artifi cially introducing pinning sites in BSCCO material used for applicatio ns, Non-linear scaling models have been used to fit our experimental r esults to estimate the elemental pinning force density and the effecti ve pinning potential.