Search

The magnetic state of α-Fe particles and the behaviour of nitrogen and zirconium during annealing in Fe96N4 and Fe85.6Zr7.6N6.8 magnetic thin films have been studied by conversion electron Mossbauer spectroscopy for 57Fe. The crystalline phases present in the Fe-N annealed films were α-Fe and γ′-Fe4N, and those in the Fe-Zr-N annealed films were α-Fe and ZrN. In the Fe-N films annealed below 300°C, about 60% nitrogen is incorporated interstitially into α-Fe and the rest is used for the formation of γ′-Fe4N. In the Fe-N film annealed at 500°C, almost all nitrogen participates in the formation of γ-Fe4N, leading to the grain growth of α-Fe particles and an increase in coercive force. The values (291–325 kOe) of internal magnetic field of iron sites in α-Fe in the Fe-Zr-N films are much smaller than that (333 kOe) of the iron site in pure α-Fe. Even if the Fe-Zr-N films were annealed at 500–700°C, some zirconium and nitrogen is still incorporated substitutionally and interstitially into α-Fe, respectively. In particular, the substitutional zirconium depresses the grain growth of α-Fe particles, perhaps due to a chemical interaction between zirconium and iron.

The magnetic state of Fe atoms at or near the interface between Fe74.3Al9.8Si15.9 sendust magnetic thin films and SiO2-based crystallized glass substrate (Fotoceram, Corning Co.) has been examined using conversion electron Mossbauer spectroscopy. The thicknesses of sputtered films are 0.05–2.0 Μm, and annealing conditions are at 500 ‡C for 1 H. The excellent soft magnetic properties are not obtained for films with a thickness of less than 0.5 Μm. The presence of ferromagnetic Fe atoms with internal magnetic fields of 24.3–24.9 MAm−1 is confirmed at or near the interface, indicating the formation of an Fe-rich phase such as Fe90Si10. The fraction of Fe atoms forming the Fe-rich phase at or near the interface is estimated to be around 20.... The formation of the Fe-rich phase is one of the main reasons for the degradation of the soft magnetic properties of sendust films deposited on SiO2-based crystallized glass substrate, even though the DO3-type ordered structure has also been formed.