High-Pressure NiAs-Type Modification of FeN

Area of Science:

• Materials Science
• High-Pressure Physics
• Solid-State Chemistry

Background:

• Investigating iron-nitrogen (Fe-N) interactions is crucial for understanding geological processes and developing advanced materials.
• Previous studies have explored Fe-N phase diagrams, but high-temperature, high-pressure behavior remains less understood.

Purpose of the Study:

• To explore the chemical reactions between iron and iron nitride (Fe2N) with nitrogen under extreme conditions.
• To identify new Fe-N compounds and their structural properties at high temperatures and pressures.

Main Methods:

• Utilized laser-heated diamond anvil cells (LHDAC) for achieving high temperatures and pressures.
• Employed synchrotron Mössbauer source spectroscopy (SMSS) for in-situ chemical analysis.
• Conducted in-situ X-ray diffraction (XRD) to determine crystal structures.
• Performed first-principles total-energy and chemical-bonding calculations for theoretical validation.

Main Results:

• Observed significant magnetic hyperfine splitting, indicating compound formation at 10-45 GPa and 1300 K.
• Identified a novel FeN phase with a NiAs-type crystal structure.
• Theoretical studies supported the formation and stability of the new FeN modification.

Conclusions:

• Confirmed the formation of a new iron nitride phase under high-temperature and high-pressure conditions.
• The NiAs-type structure of the new FeN modification was elucidated.
• This research provides fundamental insights into the Fe-N system under extreme environments.