The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates
We have found that naturally occurring grain boundaries in Tl 2Ba2CaCu2O8 (Tl-2212) thin films grown on MgO substrates have significantly higher critical current values (Jcgb) than expected. In particular, films grown on clean MgO are bi-epitaxial, containing almost exclusively 45° tilt grain bounda...
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| Format: | Journal article |
| Language: | English |
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2006
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| _version_ | 1797067473813504000 |
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| author | Dark, C Speller, S Grovenor, C |
| author_facet | Dark, C Speller, S Grovenor, C |
| author_sort | Dark, C |
| collection | OXFORD |
| description | We have found that naturally occurring grain boundaries in Tl 2Ba2CaCu2O8 (Tl-2212) thin films grown on MgO substrates have significantly higher critical current values (Jcgb) than expected. In particular, films grown on clean MgO are bi-epitaxial, containing almost exclusively 45° tilt grain boundaries with Jcgb values as high as 106 A cm-2 at 77 K. We have used high resolution electron backscatter diffraction (EBSD) to analyse the structure of both 'natural' grain boundaries in Tl-2212 films grown on MgO substrates, and 'artificial' grain boundaries forced to form in Tl-2212 films grown on lattice-matched bicrystal substrates such as LaAlO3. Polycrystalline, c-axis aligned Tl-2212 films on 'dirty' MgO contain diffuse or highly dissociated grain boundaries, thus explaining their high Jc values. Artificial grain boundaries, however, show a much more abrupt change in orientation at the grain boundary. The bi-epitaxial 45° grain boundaries are also abrupt; therefore, the high Jcgb values suggest that the local structure or chemistry at these grain boundaries is different from those of both artificial and other natural grain boundaries in polycrystalline films. © 2006 IOP Publishing Ltd. |
| first_indexed | 2024-03-06T21:56:47Z |
| format | Journal article |
| id | oxford-uuid:4d2fcd4d-64ac-42c0-97f7-fdc1b0328869 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:56:47Z |
| publishDate | 2006 |
| record_format | dspace |
| spelling | oxford-uuid:4d2fcd4d-64ac-42c0-97f7-fdc1b03288692022-03-26T15:53:59ZThe development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substratesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:4d2fcd4d-64ac-42c0-97f7-fdc1b0328869EnglishSymplectic Elements at Oxford2006Dark, CSpeller, SGrovenor, CWe have found that naturally occurring grain boundaries in Tl 2Ba2CaCu2O8 (Tl-2212) thin films grown on MgO substrates have significantly higher critical current values (Jcgb) than expected. In particular, films grown on clean MgO are bi-epitaxial, containing almost exclusively 45° tilt grain boundaries with Jcgb values as high as 106 A cm-2 at 77 K. We have used high resolution electron backscatter diffraction (EBSD) to analyse the structure of both 'natural' grain boundaries in Tl-2212 films grown on MgO substrates, and 'artificial' grain boundaries forced to form in Tl-2212 films grown on lattice-matched bicrystal substrates such as LaAlO3. Polycrystalline, c-axis aligned Tl-2212 films on 'dirty' MgO contain diffuse or highly dissociated grain boundaries, thus explaining their high Jc values. Artificial grain boundaries, however, show a much more abrupt change in orientation at the grain boundary. The bi-epitaxial 45° grain boundaries are also abrupt; therefore, the high Jcgb values suggest that the local structure or chemistry at these grain boundaries is different from those of both artificial and other natural grain boundaries in polycrystalline films. © 2006 IOP Publishing Ltd. |
| spellingShingle | Dark, C Speller, S Grovenor, C The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title | The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title_full | The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title_fullStr | The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title_full_unstemmed | The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title_short | The development of bi-epitaxial texture and high grain boundary J(c) values in Tl-2212 films on MgO substrates |
| title_sort | development of bi epitaxial texture and high grain boundary j c values in tl 2212 films on mgo substrates |
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