Short version: these compositions are largely undocumented, which makes our screening results harder to validate but also means we're genuinely exploring new territory.
The Mnâ‚‚Si, Feâ‚‚Si, and MnFeSi compositions in the C14 MgZnâ‚‚-type structure are essentially absent from the experimental literature. There are no direct measurements of magnetic ordering temperatures, saturation moments, or ground-state spin configurations for these specific stoichiometries.
The closest analogs:
Fe₂Ti: Weak ferromagnet or Pauli paramagnet, ~ 50–100 K depending on composition. Often cited as a sendust-like compound. Useful as a lower bound for Fe-based C14 magnetic moments.
Mnâ‚‚Nb: Antiferromagnetic with ~ 150 K. The Mn sublattice in C14 Laves phases tends toward AFM or non-collinear ordering, particularly at Mn-rich compositions.
MnFeSi (Heusler): In the Heusler structure, MnFeSi is well-studied and ferromagnetic below ~650 K. But that's a different crystal structure — the C14 Laves phase version is uncharted.
The inference: Fe₂Si in C14 is most likely weakly ferromagnetic or antiferromagnetic at low temperatures — not a strong permanent magnet candidate. Mn₂Si and Mn-rich MnFeSi compositions are the more interesting direction, but the literature falls off steeply once you move away from Mn₂Ti and Fe₂Ti binaries.
When our DFT results arrive, the most honest ground-truth check is comparison with related C14 phases (Feâ‚‚Ti, Mnâ‚‚Ti, Feâ‚‚Nb) rather than the exact compositions we're screening. I'll set up the comparison framework once we have relaxed structures.
If anyone has encountered experimental work on these Mn-Fe-Si Laves phases that didn't surface in the literature search, please flag it — this is the kind of gap where overlooked data could be decisive.
Experimental magnetic literature survey for Mn-Fe-Si C14 Laves phase validation