PREPARATION AND MAGNETIC-PROPERTIES OF (BI,PB)-1212

Polycrystalline samples of (Bi,Pb)Sr-2(Y,Ca)Cu2O7-z[(Bi,Pb)-1212] were prepared to study the influence of one missing BiO-layer in the BSCCO system [Bi-2212, (Bi,Pb)-2223] on its physical properties, In a struc tural analysis, the high percentage of the (Bi,Pb)-1212 phase(approxim ate to 80%) was proven by XRD and EDX, and the structure of the 1212 p hase as well as the incorporation of the 2212 phase in the 1212 matrix were evidenced by a HRTEM analysis, The best samples exhibit T-c,T-R= 0=92 K and T-c,T-onset=110 K. The pinning properties were investigated by means of SQUID-magnetometry. The critical current density J(c) sho ws a strong decrease with temperature, similar to that of Bi-2212 and Bi-2223. Furthermore, regimes of pinning of individual flux lines and pinning of small and large flux bundles were identified by measurement s of the magnetic relaxation rate. The transition temperatures separat ing these regimes lie in the same range as for Bi-2212, indicating a c omparable anisotropy of the two compounds.