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Transmission electron microscopic study of (Bi,Pb)₂Sr₂Ca₂Cu₃Ox silver-sheathed tapes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Grindatto, D. P. |
| Copyright Year | 1997 |
| Abstract | In the present work (Bi,Pb)2Sr2Ca2Cu3Ox (Bi/Pb(2223)) silver-sheathed tapes were analyzed by means of transmission electron microscopy (TEM) Emphasis was put on the phase formation of the Bi/Pb(2223) phase inside the silver sheath, on the microstructure of the superconducting oxide core, and on the effects induced by deformations at high temperatures These three issues are of particular interest regarding the production of Bi/Pb(2223) tapes with high critical transport current densities, jc The phase formation of the Bi/Pb(2223) phase inside the silver sheath was in¬ vestigated by analyzing several tapes which had undergone different heat treatment periods Only extremely few spatial transitions from Bt(2212) layers to Bt/Pb(2223) layers along the basal plane inside Bi(2212) grains were observed, and these transi¬ tions were always accompanied by considerable lattice distortions It is concluded that a layer-by-layer intercalation of extra Ca/Cu02 planes into the Bi(2212) parent crystal must be slow, provided this process really takes place Amorphous regions corresponding to a liquid phase present during the heat treatment were observed m the TEM samples, especially at early stages of the transformation These regions contained a small excess of Bi and Pb compared to Bi(2212) This finding is in contradiction to the hypothesis that the intercalation mechanism mainly generates the Bi/Pb(2223) phase, in which case a Cu and/or Ca excess would be expected A stackmg-sequence analysis provides additional evidence that the mam mechanism responsible for the Bi/Pb(2223) phase formation is a nucleation-and-growth pro¬ cess, which is orientation-controlled by the unreacted Bi(2212) grains serving as a substrate for the growing Bi/Pb(2223) phase Solid-state type transformations such as layer exchange or intercalation may also occur but must be considered as side reactions The microstructure of the superconducting oxide core in high-jc tapes was found to consist of plate-like stacks of grams with a common c-axis, termed colonies, which are connected by clean small-angle boundaries and which form a three-dimen¬ sional network structure The basic microstructural element of the "brick-wall" model, namely the pure c-axis twist boundary connecting two colonies, has not |
| File Format | PDF HTM / HTML |
| DOI | 10.3929/ethz-a-001852494 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/143283/eth-40905-01.pdf?isAllowed=y&sequence=1 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/143283/eth-40905-01.pdf;jsessionid=4E23EBBB4E3DD7A4791CCBB72B73C3DB?sequence=1 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/143283/eth-40905-01.pdf;jsessionid=41A31B5B044012D44EA27E54D07C14A2?sequence=1 |
| Alternate Webpage(s) | https://doi.org/10.3929/ethz-a-001852494 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
