Investigation of structure and magnetic properties of the as-deposited and post-annealed iron nitride films by reactive facing-target sputtering

Structure and magnetic properties of the as-deposited and post-annealed iron nitride films have been investigated systematically. A series of phases containing α-Fe, ɛ-Fe3N, ξ-Fe2N and γ″-FeN were obtained as nitrogen flow rate image increases from 0.5 to 30 sccm. An increase of the nitrogen concentration in the as-deposited films could be concluded from the phase transition with the increasing image. After being annealed, some of the iron nitride phases are decomposed and γ′-Fe4N appears in the films. The magnetic characteristics are dependent on image, which can be ascribed to the facts that the nitrogen in the films turns the valence states of Fe into Fe+ or Fedipole with high magnetic momentum or ever H-like bond Fe+/dipole with low magnetic momentum based on the bond-band-barrier correlation mechanism.