Bekheet, Maged F. ; Schlicker, Lukas ; Doran, Andrew ; Siemensmeyer, Konrad ; Gurlo, Aleksander (2018)
Ferrimagnetism in manganese-rich gallium and aluminium spinels due to mixed valence Mn2+-Mn3+ states.
In: Dalton Transactions, 47 (8)
doi: 10.1039/c7dt04765g
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Stoichiometric (MnGa2O4 and MnAl2O4) and Mn-rich (Mn1.3Ga1.7O4 and Mn1.4Al1.6O4) spinels with a small inversion degree (0.14-0.21) were obtained via a co-precipitation route followed by calcination of the as-synthesized coprecipitates at 700-1000 degrees C under different gas atmospheres (air, N-2 or argon). In situ synchrotron XRD at elevated temperatures reveals the conditions for synthesizing phase-pure materials. The stoichiometry of the samples is confirmed by inductively coupled plasma optical emission spectrometry as well as by structure refinement of neutron diffraction data of phase-pure specimens. XANES characterization reveals the average oxidation state of manganese to be +2.2 and 2.3 in Mn1.3Ga1.7O4 and Mn1.4Al1.6O4 spinels, respectively. The mixed Mn2+-Mn3+ valence states are responsible for the ferrimagnetic properties of Mn1.3Ga1.7O4 and Mn1.4Al1.6O4 samples below 48 and 55 K, respectively, as well as for a smaller optical bandgap when compared to stoichiometric spinels.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2018 |
| Autor(en): | Bekheet, Maged F. ; Schlicker, Lukas ; Doran, Andrew ; Siemensmeyer, Konrad ; Gurlo, Aleksander |
| Art des Eintrags: | Bibliographie |
| Titel: | Ferrimagnetism in manganese-rich gallium and aluminium spinels due to mixed valence Mn2+-Mn3+ states |
| Sprache: | Englisch |
| Publikationsjahr: | Februar 2018 |
| Verlag: | Royal Soc. Chemistry RSC, Cambridge, England |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Dalton Transactions |
| Jahrgang/Volume einer Zeitschrift: | 47 |
| (Heft-)Nummer: | 8 |
| DOI: | 10.1039/c7dt04765g |
| URL / URN: | http://pubs.rsc.org/en/Content/ArticleLanding/2018/DT/C7DT04... |
| Kurzbeschreibung (Abstract): | Stoichiometric (MnGa2O4 and MnAl2O4) and Mn-rich (Mn1.3Ga1.7O4 and Mn1.4Al1.6O4) spinels with a small inversion degree (0.14-0.21) were obtained via a co-precipitation route followed by calcination of the as-synthesized coprecipitates at 700-1000 degrees C under different gas atmospheres (air, N-2 or argon). In situ synchrotron XRD at elevated temperatures reveals the conditions for synthesizing phase-pure materials. The stoichiometry of the samples is confirmed by inductively coupled plasma optical emission spectrometry as well as by structure refinement of neutron diffraction data of phase-pure specimens. XANES characterization reveals the average oxidation state of manganese to be +2.2 and 2.3 in Mn1.3Ga1.7O4 and Mn1.4Al1.6O4 spinels, respectively. The mixed Mn2+-Mn3+ valence states are responsible for the ferrimagnetic properties of Mn1.3Ga1.7O4 and Mn1.4Al1.6O4 samples below 48 and 55 K, respectively, as well as for a smaller optical bandgap when compared to stoichiometric spinels. |
| Freie Schlagworte: | X-RAY-ABSORPTION; MAGNETIC-PROPERTIES; MNIN2O4 SPINEL; PHASE-DIAGRAM; K-EDGE; MNGA2O4; MN; XANES; CO; STABILITY |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Disperse Feststoffe |
| Hinterlegungsdatum: | 22 Aug 2018 14:18 |
| Letzte Änderung: | 22 Aug 2018 14:18 |
| PPN: | |
| Sponsoren: | German Research Foundation DFG: GU992/8-1, Office of Science,Office of Basic Energy Sciences, of the U.S. Department of Energy: DE-AC02-05CH11231, ALS |
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