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DC Field | Value | Language |
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dc.contributor.advisor | Greedan, J.E. | en_US |
dc.contributor.author | Eicher, Maria Sonja | en_US |
dc.date.accessioned | 2014-06-18T16:33:27Z | - |
dc.date.available | 2014-06-18T16:33:27Z | - |
dc.date.created | 2010-05-05 | en_US |
dc.date.issued | 1984-12 | en_US |
dc.identifier.other | opendissertations/1256 | en_US |
dc.identifier.other | 2442 | en_US |
dc.identifier.other | 1298168 | en_US |
dc.identifier.uri | http://hdl.handle.net/11375/5914 | - |
dc.description.abstract | <p>The structural and magnetic properties of the tri-rutile phases MTa₂O₆ (M = V, Fe, Co, Ni) were investigated. The nuclear and magnetic structures were refined from neutron powder diffraction data. The magnetic M²⁺ ions are located in planes perpendicular to the c axis. The distance between neighboring planes is approximately 4.5 Å. As a result, these compounds are quasi two dimensional magnetic systems, because the magnetic exchange interaction between ions in (001) planes is much larger than the interaction between ions in neighboring planes.</p> <p>Evidence for important two dimensional correlations has been obtained from magnetic susceptibility and heat capacity measurements. The magnetic susceptibility of these materials is characterized by a broad maximum at a temperature substantially above the ordering temperature. The experimentally observed magnetic susceptibility was compared to the predictions for 2-d quadratic layer models. The exchange interaction was antiferromagnetic in all cases. NiTa₂O₆ and VTa₂O₆ are Heisenberg systems with S = 1 and S = 3/2, respectively. The magnetic susceptibility of CoTa₂O₆ was consistent with an S = 1/2 Heisenberg model, while FeTa₂O₆ showed Ising-like behavior with S = 11.2.</p> <p>The magnetic structures of FeTa₂O₆ and VTa₂O₆ were determined. Mössbauer effect measurements were used to distinguish between two possible structural models for FeTa₂O₆. The magnetic moments of the Fe²⁺ ions points along <110> directions. The magnetic structure of VTa₂O₆ is similar, but the V²⁺ moments are oriented along <001>.</p> | en_US |
dc.subject | Chemistry | en_US |
dc.subject | Chemistry | en_US |
dc.title | Quasi Two Dimensional Magnetic Properties of the Tri-Rutile Phases MTa₂O₆, M = V, Fe, Co, Ni | en_US |
dc.type | thesis | en_US |
dc.contributor.department | Chemistry | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
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fulltext.pdf | 2.52 MB | Adobe PDF | View/Open |
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