Structural and Magnetic Properties of Sn-, Ti-, and Mg-Substituted α-Fe2O3: A Study by Neutron Diffraction and Mössbauer Spectroscopy
| Autor: | Frank J. Berry, Helen M. Palmer, Julia McManus, Colin Greaves, Örn Helgason, Ruth Williams |
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| Rok vydání: | 2000 |
| Předmět: |
Neutron powder diffraction
Materials science Dopant Neutron diffraction Condensed Matter Physics Hydrothermal circulation Electronic Optical and Magnetic Materials Ion Inorganic Chemistry Crystallography Mössbauer spectroscopy Materials Chemistry Ceramics and Composites Mossbauer spectra Physical and Theoretical Chemistry |
| Zdroj: | Journal of Solid State Chemistry. 151:157-162 |
| ISSN: | 0022-4596 |
| Popis: | Hydrothermal techniques have been used to synthesize samples of α -Fe 2 O 3 in which ca. 10% of the Fe cations have been replaced by Sn 4+ , Ti 4+ , and Mg 2+ . Neutron powder diffraction data show the dopant ions to occupy both interstitial and substitutional sites in the corundum-related α -Fe 2 O 3 structure. The details of the defect cluster depend on the charge on the dopant ion. The magnetic structures are related to that of α -Fe 2 O 3 with ambient temperature Fe 3+ moments of 4.01(5), 3.89(4), and 3.92(4) BM for Sn-, Ti-, and Mg-doped samples, respectively. The 57 Fe Mossbauer spectra recorded in situ at elevated temperatures show the Neel temperatures of Sn- and Mg-doped α -Fe 2 O 3 to be between 890 and 910 K and 910 and 930 K, respectively, as compared to 950–960 K for pure α -Fe 2 O 3 . |
| Databáze: | OpenAIRE |
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