LATTICE DISTORTION MEASUREMENT OF (BI,PB)(2)SR2CA2CU3O10-CLAD WIRES WITH MECHANICAL DEFORMATION(X OXIDE IN SILVER)

Mechanical deformation plays an important role in achieving high criti cal current density of the Ag clad Bi2223 superconductor tapes by prod ucing (00l) grain alignment. High densities of dislocation networks an d lattice distortion were therefore introduced to the Bi2223 crystals. The strain which resulted from lattice distortion provides energy for recrystallisation of Bi2223 crystals, and also affects the grain alig nment in the subsequent thermal treatments. The present work is to mea sure and study the lattice distortion in the Bi2223 crystals produced by mechanical deformation. X-ray diffraction has been used to characte rise the crystal structure, and Fourier transformation has been adapte d to separate the peak broadening effects of lattice distortion and gr ain size. The results indicate that certain amounts of lattice distort ion were produced in the brittle Bi2223 oxide by mechanical deformatio n, and multi-step structures with the thickness equivalent to 6 layers of Bi2223 oxide cells (similar to 22 nm) along the c-axis direction w ere built in the Bi2223 tapes with heavy mechanical deformation. (C) 1 998 Elsevier Science B.V.