PROPERTIES AND STRUCTURE OF THE F-DOPED (BI,PB)-SR-CA-CU-O SUPERCONDUCTOR

By using TEM, XPS, IR, position annihilation and differential specific heat measurements, the properties and structure of the F-doped (Bi, P b)-Sr-Ca-Cu-O superconductor have been studied. The results show that the fluorine atoms are homogeneously distributed in superconducting ph ase and substituted for the oxygen atoms at O(2) crystallographic site s; the Pb-F and Cu-F bonds are formed. F-doping results in the varianc e of the incommensurate modulation structure, the increase of the poin t defects and chemical pressure, the enhancement of flux pinning effec t and the change of the electronic structure and chemical bond, and gr eatly improves superconductive properties of the 2223 phase (Bi, Pb)-S r-Ca-Cu-O.