Results for “Fe3Mo3N” | Engineering Papers

DOE OSTI2020

Materials Data on Fe3Mo3N by Materials Project

Fe3Mo3N crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Mo is bonded in a 2-coordinate geometry to six Fe and two equivalent N atoms. There are four shorter (2.72 Å) and two longer (2.73 Å) Mo–Fe bond lengths. Both Mo–N bond lengths are 2.13 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to six equivalent Mo and six equivalent Fe atoms to form FeFe6Mo6 cuboctahedra that share edges with six equivalent NMo6 octahedra and faces with six equivalent FeFe6Mo6 cuboctahedra. All Fe–Fe bond lengths are 2.35 Å. In the second Fe site, Fe is bonded in a distorted q6 geometry to six equivalent Mo and six Fe atoms. All Fe–Fe bond lengths are 2.40 Å. N is bonded to six equivalent Mo atoms to form NMo6 octahedra that share corners with six equivalent NMo6 octahedra and edges with six equivalent FeFe6Mo6 cuboctahedra. The corner-sharing octahedral tilt angles are 47°.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Thin-Film Stabilization and Magnetism of η -Carbide-Type Iron Nitrides

Transition-metal nitrides in ..eta..-carbide-type structures exhibit unusual bonding motifs and proximity to magnetic instabilities. Yet they remain unexplored in thin-film form due to the difficulty of stabilizing nitrogen-poor ternaries among competing phases. Here, we report the thin-film synthesis and phase-stability mapping of the ..eta..-nitride systems Fe-W-N and Fe-Mo-N. Amorphous Fe-M-N (M = W, Mo) combinatorial libraries deposited by reactive cosputtering crystallize upon rapid thermal annealing, enabling systematic identification of synthesis windows as a function of composition and annealing temperature. Using laboratory powder X-ray diffraction and synchrotron grazing incidence wide-angle X-ray scattering, we establish that Fe 3 Mo 3 N-based ..eta..-carbide phases form over a substantially broader compositional and thermal range than W-based compositions, where ..eta.. structures are stabilized only when the films are Fe-rich. These trends are rationalized using mixed chemical-potential vs composition phase diagrams that capture the narrow nitrogen chemical-potential stability of ..eta..-nitrides. Magnetic measurements reveal that ferromagnetism is induced in Fe-rich Fe 3.54 Mo 2.46 N with a small exchange-bias-like response that is absent in Fe 3 W 3 N-based compositions, highlighting the sensitivity of magnetic behavior to modest deviations from stoichiometry. This work establishes practical thin-film synthesis routes for ..eta..-nitride materials and demonstrates how composition can be tuned to access emergent magnetic phenomena in these complex nitrides.

36 MATERIALS SCIENCE↗