Crystallographic origins of fast-ion conduction in pyrochlore
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2010
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| Online Access: | http://hdl.handle.net/1721.1/50456 |
| _version_ | 1826195911065206784 |
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| author | Eberman, Kevin W. (Kevin Wilmot), 1971- |
| author2 | Bernhardt J. Wuensch. |
| author_facet | Bernhardt J. Wuensch. Eberman, Kevin W. (Kevin Wilmot), 1971- |
| author_sort | Eberman, Kevin W. (Kevin Wilmot), 1971- |
| collection | MIT |
| description | Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998. |
| first_indexed | 2024-09-23T10:17:47Z |
| format | Thesis |
| id | mit-1721.1/50456 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:17:47Z |
| publishDate | 2010 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/504562020-08-27T13:16:01Z Crystallographic origins of fast-ion conduction in pyrochlore Eberman, Kevin W. (Kevin Wilmot), 1971- Bernhardt J. Wuensch. Massachusetts Institute of Technology. Department of Materials Science and Engineering Materials Science and Engineering Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998. Includes bibliographical references (p. 129-132). We have examined the crystallographic origins of fast-ion conduction in oxides with the pyrochlore structure-type, ideally A2B2O7, a superstructure of (A,B)20 3.5 defect fluorite-like array. These materials have technological promise for use in electrochemical devices such as oxygen sensors and solid-oxide fuel-cells. The pathway for ion conduction proposed by several authors has been a jump between equivalent nearest-neighbor oxygen sites through the tetrahedral edges of the relatively-immobile cation array. Substitution of a third cation species in slid-solution in the B site, A2(B-yB'y)2O7, results in a marked change in the structure and properties of the materials which is not fully understood. As the average radius of the cations occupying the B-site increases (with changing composition) towards that of the larger average radius of the cations occupying the Asite, a tendency for increasing disorder has been observed, where complete disorder corresponds to the fluorite structure. A decrease in Frenkel-defect formation-energy and an increase in the migration enthalpy accompanies the disordering. We have executed several studies of pyrochlore structures employing neutron and x-ray powder diffraction. In particular, we have focused on high-temperature in-situ experiments that should better correspond to the structure for which the conductivity measurements were made at elevated temperature ... by Kevin W. Eberman. Ph.D. 2010-01-07T20:41:31Z 2010-01-07T20:41:31Z 1998 1998 Thesis http://hdl.handle.net/1721.1/50456 42077776 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 132 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Materials Science and Engineering Eberman, Kevin W. (Kevin Wilmot), 1971- Crystallographic origins of fast-ion conduction in pyrochlore |
| title | Crystallographic origins of fast-ion conduction in pyrochlore |
| title_full | Crystallographic origins of fast-ion conduction in pyrochlore |
| title_fullStr | Crystallographic origins of fast-ion conduction in pyrochlore |
| title_full_unstemmed | Crystallographic origins of fast-ion conduction in pyrochlore |
| title_short | Crystallographic origins of fast-ion conduction in pyrochlore |
| title_sort | crystallographic origins of fast ion conduction in pyrochlore |
| topic | Materials Science and Engineering |
| url | http://hdl.handle.net/1721.1/50456 |
| work_keys_str_mv | AT ebermankevinwkevinwilmot1971 crystallographicoriginsoffastionconductioninpyrochlore |