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Two-phase microstructures generating efficient pinning centers in the heavily Pb-substituted Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals

Journal Article · · Journal of Solid State Chemistry
; ;  [1]
  1. Kyoto Univ., Uji (Japan). Inst. for Chemical Research
Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-2212) single crystals with a large amount of Pb substituted for Bi were grown by the floating zone method, and their magnetic properties and microstructures have been studied by means of SQUID magnetometory and electron microscopy. Critical current density (J{sub c}) increases dramatically beyond a critical Pb content of {approximately} 0.4 per formula unit, where characteristic two-phase microstructures are revealed by electron microscopy. The single crystals consist of alternating thin (several tens of nanometers) lamellar plates of two phases with the (010) interface, one with lower Pb content ({approximately} 0.4) and a modulated structure and the other with higher Pb content ({approximately} 0.6) and a modulation-free structure. The relative volume fraction of the latter phase increases systematically with increasing starting Pb content. At higher Pb content, lamellas with irregularly stepped interfaces and bubbles of the latter phase embedded in the matrix of the former phase are also observed. The growth mechanism is discussed in terms of unidirectional solidification of eutectic or eutectoid.
OSTI ID:
642225
Journal Information:
Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 138; ISSN 0022-4596; ISSN JSSCBI
Country of Publication:
United States
Language:
English