Ternary nitride GaFe(3)N: an experimental and quantum-theoretical study

Area of Science:

• Materials Science
• Solid State Chemistry
• Computational Materials Science

Background:

• Gallium iron nitride (GaFe(3)N) synthesis via a two-step ammonolysis reaction was previously reported.
• Understanding the phase purity and structural properties of Ga(x)Fe(4-x)N is essential for its applications.

Purpose of the Study:

• To reinvestigate the synthesis of phase-pure GaFe(3)N.
• To elucidate the complex lattice parameter behavior in the Ga(x)Fe(4-x)N series.
• To understand the influence of magnetic ordering on structural properties.

Main Methods:

• Thermochemical calculations to determine optimal reaction temperatures.
• High-resolution X-ray diffraction (XRD) using Mo Kα(1) radiation for precise structural analysis.
• Density-functional theory (DFT) calculations to model structural and magnetic properties.
• Magnetic susceptibility measurements to determine magnetic ordering.

Main Results:

• High-temperature routes are necessary to prevent the formation of competing Gallium Nitride (GaN) phases.
• The lattice parameter of Ga(x)Fe(4-x)N exhibits complex, non-linear behavior, differing from previous Vegard-like observations.
• A transition in magnetic ordering from ferromagnetic in γ'-Fe(4)N to antiferromagnetic in GaFe(3)N was observed and theoretically modeled.
• DFT calculations successfully reproduced the observed magnetic ordering and structural models.

Conclusions:

• The synthesis of phase-pure GaFe(3)N requires high temperatures.
• Magnetic properties significantly impact the lattice parameter behavior in Ga(x)Fe(4-x)N alloys.
• The atomic ordering in GaFe(3)N is favored due to strong iron-nitrogen affinity, consistent with theoretical predictions.