Ordering in Tl(sub 2)CaBa(sub 2)Cu(sub 2)O(sub 8) and Tl(sub 2)Ba(sub 2)CuO(sub 6) studied by pair distribution function and Rietveld analysis.

摘要

Rietveld analysis indicates that the only long-range structural variation in Tl(sub 2)CaBa(sub 2)Cu(sub 2)O(sub 8) with temperature is a shift of O(2) away from Cu and toward Ba with increasing T. Atomic pair distribution function analysis on two samples of Tl(sub 2)Ba(sub 2)CuO(sub 6), one superconducting, the other not, shows substantial differences in their short range structure, but similar medium range structures, while Rietveld analysis shows very similar lattice constants and long-range structures. 5 refs., 2 figs.