About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
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| Symposium
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Advances in Magnetism and Magnetic Materials
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| Presentation Title |
Understanding Chemical Bonding and Phase Stability in Sm₂Fe₁₇-based interstitial magnet |
| Author(s) |
Xubo Liu, Ikenna Nlebedim |
| On-Site Speaker (Planned) |
Xubo Liu |
| Abstract Scope |
Sm2Fe17X3 (X=C,N) interstitial phases exhibit comparable or even better intrinsic magnetic properties than Nd2Fe14B. However, their poor phase stability remains a major obstacle to developing bulk magnets. First-principles calculations indicate that Sm2Fe17N3 has negative formation (-6.4 eV/f.u.) and decomposition energies (-0.74 eV/f.u.), while Sm2Fe17C3 has negative formation energy (-2.0 eV/f.u.) but a small positive decomposition energy (0.48 eV/f.u.), which is responsible for the better thermal stability of Sm2Fe17C3 than Sm2Fe17N3. The asymmetry in bonding between Sm–X and Fe–X interactions creates local structural distortions and degrades the phase stability of Sm2Fe17X3. The project Crystal Orbital Hamilton Population analysis indicates that the Fe–X bonding becomes negative near the Fermi level, signifying anti-bonding contributions that reduce structural stability. Partial replacement of Fe by M=Al, Si, and Ga can enhance phase stability. These elements prefer to form Sm-M bonds rather than M-M bonds, which strengthens the Sm-Fe chemical bonding.
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| Proceedings Inclusion? |
Planned: |
| Keywords |
Magnetic Materials, Computational Materials Science & Engineering, |