Structural changes of maghemite during thermal conversions of iron minerals - AFM and Mössbauer spectroscopy study
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F01%3A00001392" target="_blank" >RIV/61989592:15310/01:00001392 - isvavai.cz</a>
Result on the web
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DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
Structural changes of maghemite during thermal conversions of iron minerals - AFM and Mössbauer spectroscopy study
Original language description
Ultrafine superparamagnetic particles of maghemite with the size of 4-10 nm were prepared by conversion of almandine garnet at 800 °C in combination with the postprocessing sedimentation separation (sample I). Larger ferrimagnetic crystallites of maghemite (>30 nm) were synthesized by air oxidation of magnetite at 250 °C (sample II). The heating of sample II resulted in the direct formation of hematite while the orthorhombic e-Fe2O3 was observed during the thermal treatment of sample I at 850 °C. The RTMössbauer spectrum of e-Fe2O3 is complex and can be approximated by four sextets corresponding to the non-equivalent Fe3+ positions in the structure. Two of the octahedral sites are characterized by close Hhyp values (~ 46 T), affecting their overlapping. The third octahedral site exhibits a smaller Hhyp (~ 40 T). The unusually low Hhyp value (~ 26 T) corresponds to the tetrahedral position. AFM analysis of the mixture of polymorphs allowed to distinguish the elongated particles of e-Fe
Czech name
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Czech description
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Classification
Type
J<sub>x</sub> - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
CF - Physical chemistry and theoretical chemistry
OECD FORD branch
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Result continuities
Project
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Continuities
Z - Vyzkumny zamer (s odkazem do CEZ)
Others
Publication year
2001
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Bulletin de liaison de la Sociéte Francaise de Minéralogie et de Cristallographie
ISSN
0999-5870
e-ISSN
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Volume of the periodical
13
Issue of the periodical within the volume
N
Country of publishing house
FR - FRANCE
Number of pages
2
Pages from-to
115-116
UT code for WoS article
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EID of the result in the Scopus database
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