MAGNETIC AND HRTEM STUDIES OF IODINE-INTERCALATED BI2SR2CACU2OY

Magnetic irreversibility data is presented for iodine intercalated Bi2 Sr2CaCu2Oy single crystals. Iodine transfers charge both to the CuO2 p lanes and the BiO bilayers. The possibility of enhanced coupling along the c-axis through increased conductivity in the rocksalt block is no t borne out in the irreversibility fields, H-irrl, suggesting either t hat Bi2Sr2CaCu2O(y) is firmly in the 2-dimensional limit, or that any increase in the c-axis coupling is balanced by larger separation of th e CuO2 planes. Magnetic relaxation data is also discussed. Electron mi croscopy reveals two forms of in-plane defect associated with iodine i ntercalation, one resulting from faults in realignment of the BiO laye rs from an a/2 staggered sequence to a registered sequence, and the ot her related to the packing of I-3. chains in the lattice.