HREM study of the 30 K superconductor Bi[sub 2]Sr[sub 4]Cu[sub 2]CO[sub 3]O[sub 8]

Journal Article · Mon Jan 31 23:00:00 EST 1994 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1994.1051· OSTI ID:5115198

Hervieu, M; Pelloquin, D; Raveau, B ^[1]; Caldes, M T ^[2]

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1. Universite de Caen (France)
2. Instituto de Ciencias de Materiales, Bellaterra (Spain)

The structure and the microstructure of a new high T[sub c] superconductor Bi[sub 2]Sr[sub 4]Cu[sub 2]CO[sub 3]O[sub 8] have been studied by high-resolution electron microscopy. The [110] orientation allows us to image the layer stacking, and [010] calculated images allow us to interpret the contrast. The oxycarbonate Bi[sub 2]Sr[sub 4]Cu[sub 2]CO[sub 3]O[sub 8] exhibits a modulated structure; the mean value of the component of the modulation vector along b is 8.85 but this periodicity is not constant. The relative arrangement of the double bismuth layers [BiO][sub 2] involves the periodic compression of the intermediate layer, resulting in a strong variation of the contrast. The existence of additional slices, [Sr[sub 2]CuCO[sub 3]O[sub 2]] or [Bi[sub 2]Sr[sub 2]CuO[sub 6]], suggests the existence of a large family which can be formulated [Bi[sub 2]Sr[sub 2]CuO[sub 6]][sub n] [Sr[sub 2]CuCO[sub 3]O[sub 2]][sub n]; n[prime] = 1 to 5, and n = 1 and 2 have been observed. The existence of a shearing mechanism along c involves the connection of layers of different natures through the boundary; this mechanism is not only observed as isolated defects but can lead to the formation of a new [open quotes]collapsed oxycarbonate[close quotes] phase. Other structural features such as the micalike morphology and the existence of 90[degrees] oriented domains are discussed.

• OSTI ID: 5115198
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Journal Issue: 2 Vol. 108:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
COPPER COMPOUNDS
ELECTRON MICROSCOPY
HIGH-TC SUPERCONDUCTORS
MICROSCOPY
MILLER INDICES
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS