Challenge to the Synthesis of α-Fe16N2 Compound Nanoparticle with High Saturation Magnetization for Rare Earth Free New Permanent Magnetic Material

Single-phase alpha ''-Fe16N2 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 alpha ''-Fe16N2 nanoparticles exhibited saturation magnetization (M-s) of 234 emu/g at 5 K and a magnetocrystalline anisotropy constant (K-u) of 9.6 x 10(6) erg/cm(3). These magnetic properties of this alpha ''-Fe16N2 nanoparticles suggest that a new path for a possible candidate of the rare-earth-free permanent magnet material with a high M-s. (C) 2013 The Japan Society of Applied Physics