Title :
Superconductivity and crystal structure in the Bi-Pb-Sr-Ca-Cu-O system
Author :
Zhu, Xing ; Feng, Sunql ; Zhang, Jian ; Gan, Zizhao
Author_Institution :
Dept. of Phys., Peking Univ., Beijing, China
fDate :
3/1/1989 12:00:00 AM
Abstract :
BiPbSrCaCuO superconductors with various nominal compositions have been studied. Tc,zer0=111 K and an AC Meissner effect of 93.1% have been obtained in a (Bi0.8Pb0.2)2Sr2Ca2 -Cu3Ox sample. The authors have also synthesized a single-phase (Bi0.8Pb0.2)2Sr2Ca2 Cu3Ox sample. The crystal structure of the superconducting phase has been determined by transmission electron microscopy, convergent beam electron diffraction, and powder X-ray diffraction. The crystal structure of the Pb-doped system has a tetragonal unit cell (a=b=3.823 Å, c=37.074 Å), space group I4/MMM. The atomic coordinates have been determined. Unlike the Bi-based system without Pb, the Pb-doped 2223 phase has very weak or no modulation structure, which in turn changes the symmetry from pseudo-tetragonal to tetragonal. The relationship between synthesis conditions and superconductivity is discussed
Keywords :
Meissner effect; bismuth compounds; calcium compounds; crystal atomic structure of inorganic compounds; crystal symmetry; electron diffraction examination of materials; high-temperature superconductors; lead compounds; strontium compounds; superconducting transition temperature; transmission electron microscope examination of materials; 111 K; AC Meissner effect; Bi1.6Pb0.4Sr2Ca2Cu 3Ox; TEM; atomic coordinates; convergent beam electron diffraction; critical temperature; crystal structure; crystal symmetry; high temperature superconductor; modulation structure; powder X-ray diffraction; single-phase; synthesis conditions; Conductivity; Electron beams; Electron microscopy; Phase modulation; Physics; Powders; Solid state circuits; Superconductivity; Transmission electron microscopy; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
