Ikeda, Yuji ; Lehmann, Tanja S. ; Widenmeyer, Marc ; Coduri, Mauro ; Grabowski, Blazej ; Niewa, Rainer (2020)
Crystal structure and phase stability of Co2N: A combined first-principles and experimental study.
In: Journal of Alloys and Compounds, 854
doi: 10.1016/j.jallcom.2020.156341
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
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.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2020 |
| Autor(en): | Ikeda, Yuji ; Lehmann, Tanja S. ; Widenmeyer, Marc ; Coduri, Mauro ; Grabowski, Blazej ; Niewa, Rainer |
| Art des Eintrags: | Bibliographie |
| Titel: | Crystal structure and phase stability of Co2N: A combined first-principles and experimental study |
| Sprache: | Englisch |
| Publikationsjahr: | 6 August 2020 |
| Verlag: | Elsevier BV, Science Direct |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Journal of Alloys and Compounds |
| Jahrgang/Volume einer Zeitschrift: | 854 |
| DOI: | 10.1016/j.jallcom.2020.156341 |
| URL / URN: | https://www.sciencedirect.com/science/article/pii/S092583882... |
| Kurzbeschreibung (Abstract): | 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. |
| Freie Schlagworte: | Cobalt nitrides, Phase stability, First-principles calculations, X-ray diffraction, Differential scanning calorimetry |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Werkstofftechnik und Ressourcenmanagement |
| Hinterlegungsdatum: | 09 Okt 2020 06:11 |
| Letzte Änderung: | 09 Okt 2020 06:11 |
| PPN: | |
| Projekte: | This work was supported by the European Research Council (ERC) under the EU’s Horizon 2020 Research and Innovation Programme (Grant Agreement No. 639211)., We also highly acknowledge the granted beam time and financial support by the European Synchrotron Radiation Facility, Grenoble, France. |
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