The Ternary Nitrides GaFe3N and AlFe3N: Improved Synthesis and Magnetic Properties

The recently published two-step ammonolysis was adapted to the first synthesis of GaFe3N as a pure phase and AlFe3N with a very high phase purity. Similar to archetypal gamma'-Fe4N (a = 3.7900(6) angstrom), the ternary nitride GaFe3N adopts a perovskite-like structure in space group Pm (3) over barm with a slightly enlarged lattice parameter of a = 3.7974(1) angstrom. The magnetic characterization clearly evidences that GaFe3N is an antiferromagnet. The systematic exchange of Ga by Fe in going from GaFe3N to gamma'-Fe4N results in a change from antiferromagnetic to ferromagnetic behavior. In contrast, the homologous ternary nitride AlFe3N shows a statistical Al/Fe substitution which results in space group Fm (3) over barm. AlFe3N can be classified as a soft ferromagnetic nitride.