Variation of superlattice structure of the Bi/sub 2/Sr/sub 2-x/CuO/sub 6-y/ superconductor with composition and thermal history
Single crystals of Bi/sub 2/Sr/sub 2-x/CuO/sub 6-y/, (0.1 < x < 0.5, 0 < y < 0.5), were examined using x-ray diffraction techniques. Diffractometer scans of theta--2theta taken normal to the cleavage planes displayed the even (00/ell/) reflections from /ell/ = 2 to 26. Weak satellite peaks were observed on either side of each main (00/ell/) reflection, and their intensities relative to the main peak increased as 2theta was increased. With decreasing Sr content, the satellite peaks systematically moved away from the position of the main reflection. In contrast, the positions of the satellite peaks did not change with oxygen content which was varied by up to 0.5 oxygen atoms per formula unit. Depending on the Sr content of the crystals, generally incommensurate modulations were found with the superstructure periodicity ranging between /approximately/1/5b* + 0.29c* and /approximately/1/5b* + 0.65c*. The modulation in Bi/sub 2-x/CuO/sub 6-y/ has two components. The component along the b* direction is smaller to the superstructure observed in Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 7/ crystals and thus is probably due to the mismatch between the Bi/sub 2/O/sub 2/ layer and the CuO/sub 2/ layer. The additional component along c* may be due to the ordering of Sr vacancies. 12 refs., 3 figs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6049529
- Report Number(s):
- CONF-890426-8; ON: DE89011612
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CHALCOGENIDES
CHEMICAL COMPOSITION
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
SCATTERING
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X-RAY DIFFRACTION