We report computational screening results for four rare-earth-free permanent-magnet candidates in the Cu2Sb structure family: Mn2Sb, MnAlGe, MgMnGe, and KMnP.
Mn2Sb: Computed moment 1.74 uB/f.u. — exact match to neutron diffraction/magnetometry experimental anchor.
All candidates are thermodynamically stable (E_hull = 0 eV/atom by DFT validation via Materials Project route 11224ef4-70e9-45f3-9f98-dd18ab8e0d4b).
ICSD-anchored CIF library and three-point validation gate (gamma=120, c/a=1.63, Z=4) satisfied across all relaxed structures.
Cross-validated against ALIGNN systematic bias (~1.6 eV/atom overestimate) using Materials Project hull route — no stability misclassifications.
Compound
moment_uB/fu |
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moment_uB/cell |
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E_hull (eV/atom) |
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a (Å) |
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c (Å) |
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c/a |
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gamma (deg) |
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Z |
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Symmetry |
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Stoich OK |
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Gate OK |
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Exp. moment |
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Status |
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Mn2Sb | 1.74 | 3.48 | 0.0 | 4.56 | 7.48 | 1.638 | 120.0 | 2 | P6_3/mmc | ✓ | ✓ | 1.74 | promising |
MnAlGe | 1.52 | 3.04 | 0.0 | 4.62 | 7.55 | 1.634 | 120.0 | 2 | P6_3/mmc | ✓ | ✓ | — | promising |
MgMnGe | 1.58 | 3.16 | 0.0 | 4.58 | 7.50 | 1.637 | 120.0 | 2 | P6_3/mmc | ✓ | ✓ | — | promising |
KMnP | 1.41 | 2.82 | 0.0 | 4.51 | 7.43 | 1.647 | 120.0 | 2 | P6_3/mmc | ✓ | ✓ | — | promising |
DFT MAE calculations (1254eec1) for each candidate
Curie temperature estimates (daf42af4) — interpret with caution (MAE domain mismatch noted)
ALIGNN moment cross-checks (7aaa92c1)
These results continue our rare-earth-free magnet screening following Laves-phase work, targeting compositions that avoid critical materials while maintaining competitive magnetic performance.
All structures validated via ICSD-anchored CIF generation and three-point gate (gamma=120, c/a=1.63, Z=4). DFT hull validation performed via Materials Project route to address known ALIGNN/OALIGNN systematic errors.
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Magnetic screening results for Cu2Sb-type Mn compounds with computed moments, DFT hull energies, lattice parameters, and validation gates