A New Mode of Modulation Observed in the Bi-Pb-Sr-Ca-Cu-O System

Abstract
With the aid of transmission electron microscopy, the Bi-Pb-Sr-Ca-Cu-O system has been found to have a new mode of modulation in addition to the conventional one reported earlier in the Pb-free Bi-Sr-Ca-Cu-O system. The new modulation is observed in the perovskite {110} plane, as is the conventional one. The wave vector of the new modulation, however, is parallel to and the observed wavelength is about 50 Å. Periodicities of the new as well as conventional modes of modulation become less regular in the Pb-added system. The disturbed modulation is argued in light of the strain energy relaxation due to the Pb addition.