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http://dx.doi.org/10.18419/opus-11397
Autor(en): | Ikeda, Yuji Lehmann, Tanja S. Widenmeyer, Marc Coduri, Mauro Grabowski, Blazej Niewa, Rainer |
Titel: | Crystal structure and phase stability of Co2N: a combined first-principles and experimental study |
Erscheinungsdatum: | 2021 |
Dokumentart: | Zeitschriftenartikel |
Seiten: | 10 |
Erschienen in: | Journal of alloys and compounds, 854 (2021), 156341 |
URI: | http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-114144 http://elib.uni-stuttgart.de/handle/11682/11414 http://dx.doi.org/10.18419/opus-11397 |
ISBN: | 0925-8388 |
Zusammenfassung: | The crystal structure and phase stability of Co2N are revisited based on experiments and first-principles calculations. Powder X-ray diffraction (PXRD) measurements and Rietveld refinements clearly confirm that the stable crystal structure of Co2N is an isotype of η-Fe2C and Co2C with the space group Pnnm rather than the closely related ζ-Fe2N with the space group Pbcn. The refined lattice parameters of Co2N in the Pnnm structure are a = 4.6108(1) Å, b = 4.3498(1) Å, c = 2.85592(7) Å, obtained from X-ray diffraction using synchrotron radiation. Furthermore, differential scanning calorimetry (DSC) with subsequent diffraction experiments reveal an endothermal transition to an ε-type order at 398 °C followed by an exothermal decomposition at 446 °C. First-principles density-functional-theory (DFT) calculations including the Hubbard U correction (DFT+U) demonstrate that it is essential for transition metal nitrides to consider strong electron correlation to predict the correct experimental structure and magnetic state. In particular, an effective value of Ueff = 2.75 eV can be utilized to obtain an antiferromagnetic Pnnm phase of Co2N in agreement with experiments. |
Enthalten in den Sammlungen: | 03 Fakultät Chemie |
Dateien zu dieser Ressource:
Datei | Beschreibung | Größe | Format | |
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1-s2.0-S0925838820327055-main.pdf | 2,27 MB | Adobe PDF | Öffnen/Anzeigen |
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