Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Transition-metal nitrides in η-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 η-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 η-carbide phases form over a substantially broader compositional and thermal range than W-based compositions, where η 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 η-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 η-nitride materials and demonstrates how composition can be tuned to access emergent magnetic phenomena in these complex nitrides.
Source: Chemistry of Materials
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G1229526393, G1285306620, G1286251239, G1723423531, G1847291448, G2371548206, G262532246, G303061748, G3262563802, G357145406, G401452090, G4235786860, G498139845, G5570207115, G566293355, G5765906131, G6317861850, G6550344761, G6796042841, G6965541988, G7021897321, G7283024673, G7463374569, G7626931543, G8142658735, G834333836, G8382000481, G847654844, G911061179, G944719100, G969889393
OpenAlex ID: W7165041949