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Fe‐Al‐Si‐Ni supersendust films containing 2.7 at. % Ni atoms with a thickness of 1 μm were deposited on crystallized‐glass substrates by rf planar magnetron sputtering, and the changes in magnetic properties and structure due to the sputtering conditions and annealing were examined. The films with excellent soft magnetic properties and high magnetic‐flux density which are good candidates for new recording‐head materials were obtained by annealing as‐deposited films at 500 °C. It was found through conversion electron Mossbauer spectroscopy (CEMS) that the disordered structure of α type in as‐sputtered films transformed into the ordered structure consisting of a mixture of B2 and DO3 types at the temperature of 500 °C. The CEMS studies also revealed that Ni atoms are located at the corner in the bcc structure.

The structural relaxation in (Ni,Fe)75Si10B15 metallic glasses has been studied by measuring resistivity changes and Mossbauer spectra. The sign and magnitude of resistivity changes due to the relaxation depend strongly on the Ni/Fe ratio. The isothermal resistivity changes fit well the nonlinear kinetic form, indicating that the fluctuation of local environments of Ni and Fe atoms is very large and Ni and Fe atoms in Ni‐Fe‐Si‐B metallic glasses are mobile compared with Co and Fe atoms in Co‐Fe‐Si‐B metallic glasses. The compositional dependence and kinetic parameters for reversible resistivity changes and Mossbauer spectra strongly support that the reversible structural relaxation corresponds to the reversible short‐range ordering between Ni and Fe atoms.

Mossbauer spectroscopy was carried out to elucidate the magnetic structure of Fe16N2 with the giant magnetization. Samples were prepared by ion‐implant nitrification of single‐crystal iron films, followed by an annealing at 150 °C for 60 h. The nitrification developed three Fe atom environments, attributable to three different Fe sites in Fe16N2 structure. The magnetic moments of the first, second, and third nitrogen neighbor Fe atoms were determined to be 1.3, 2.5, and 3.8 μB, respectively. The quadrupole effect in Fe16N2 was interpreted consistently on the basis of the consideration that the magnetization is directed along [001] and nitrogen atoms had a negative charge.

Nitrogen ions were implanted in 200‐nm‐thick single crystalline iron films for a stoichiometric concentration of Fe16 N2 (11.1 at. %) by way of a multiple implantation. X‐ray diffraction revealed that the as‐implanted films were composed of 70% nitrogen martensite and 30% residual α‐Fe. A slight amount of α‘‐martensite, that is, Fe16 N2, was detected but the principal constituent of the nitrogen martensite was α’‐martensite. The saturation magnetic moment increased by 13.4 % with the implantation. Annealing the implanted films at 150 °C for 2 h in vacuum resulted in an increase in a constituent of the α‘ phase, but affected the magnetic moment only slightly. It was deduced that the saturation magnetization of the nitrogen martensite is ∼257 emu/g at room temperature. It was also found that the implantation induced a perpendicular magnetic anisotropy due to the characteristics of the nitrogen martensite.

Synthesis of thin films of Fe16N2 has been investigated by use of a high‐dose nitrogen ion implantation into thin iron films. Nitrogen molecular ions of N+2 were accelerated to 150 keV and implanted into α‐iron films with a thickness of 200 nm. As a result of an implantation with the dose of 4.0×1016 (N2/cm2), 35% of the α‐Fe was transformed into an iron nitride with a body‐centered‐tetragonal (bct) structure. The c axis of the bct lattices was oriented perpendicularly to the film plane. It was found that nitrogen implantation into iron films gives rise to both an increase in the spontaneous magnetization and a perpendicular anisotropy. These facts are explained on the basis of the bct nitride formation and the c‐axis orientation. Conversion electron Mossbauer spectroscopy was used to study hyperfine structures and magnetic properties of the implanted films. Three different Fe sites corresponding to the bct nitride were recognized in a spectrum of the implanted film. The maximum hyperfine field was 372.8 ...