TEM STUDY OF THE IODINE-INTERCALATED BI1.5PB0.5SR2CA2CU3O10+X

The partial substitution of Pb for Bi made it possible to prepare sing le phase 2223 and iodide intercalated I-2223 BiSrCaCuO compounds. Both compounds were studied by TEM, HRTEM, X-ray diffraction, and electric al resistivity. A change in symmetry occurs upon intercalation, likely a Bbmb to Pbm2 transition, and the change in the stacking sequence of the perovskite blocks was directly observed by HRTEM. Low temperature electrical resistivity measurements showed a metallic type conduction with critical temperatures of 105 K and 83 K, respectively. The resis tivity at room temperature was 1.6 x 10(-3) Ohm cm for 2223 and 0.14 O hm cm for I-2223.