Challenge to the Synthesis of α''-Fe₁₆N₂Compound Nanoparticle with High Saturation Magnetization for Rare Earth Free New Permanent Magnetic Material

Single-phase α''-Fe 16 N 2 nanoparticles have been synthesized with high reproducibility in gram amounts for the first time. The nanoparticles were obtained through the various kinds of successive procedure starting from the reduction of Fe-oxides, followed by nitriding in an atmosphere with very low moisture and oxygen contents of less than 1 ppm through the entire process. The single-phase α''-Fe 16 N 2 nanoparticles exhibited saturation magnetization ( M s ) of 234 emu/g at 5 K and a magnetocrystalline anisotropy constant ( K u ) of 9.6 × 10 6 erg/cm 3 . These magnetic properties of this α''-Fe 16 N 2 nanoparticles suggest that a new path for a possible candidate of the rare-earth-free permanent magnet material with a high M s .