Effects of nitrogen in the (Fe1−xNix)4N compounds (0 ≤x ≤ 0.6)

Abstract

Single phase y'-Fe&-type (Fel_,Ni,)fi compounds and Fel-,Ni, (0 5 x 5 0.6) alloys are synthesized and studied by X-ray diffraction and Mossbauer spectroscopy. The structure changes from b.c.c. to f.c.c. when Fel_,Ni, (x 5 0.25) alloys are nitrided to (Fel-,Ni,)4N. The lattice expansion Aa/a is 5.3% for f.c.c. Fel-,Ni, alloys (x > 0.25) on nitrogenation. The observed decrease in the average iron hyperfine fields with nitrogenation, amounting to 8 to 14 T, is explained by the volume expansion and the chemical bond effects. The chemical bond effect is about three times larger than the volume effect.The increase in the average isomer shift after nitriding is mainly due to the effect of chemical bonds, which changes the electronic configuration of iron.

X-ray diffraction and Mössbauer study of (Fe1−xNix)4N (0.2≤x≤0.6) films

“…Therefore, the occupation preference of the nickel in the (Fe 1−x Ni x ) 4 N can be discussed by the high nickel substitution. This has been discussed in detail in the literature [13,16]. If the recoilless fraction of iron atom at every crystal site is the same, then we have the formula:…”

Mössbauer study of (Fe1−xCux)4N (0.05⩽x⩽0.15) films

“…This can be correlated to the alteration of local environment of the Fe atoms due to Cu atoms substitution and to the change of lattice parameters. However, the average isomer shift /ISS remains unchanged 0.28 mm/s for x ¼ 0.05 and 0.1 and increased to 0.35 mm/s for x ¼ 0.15 due to the change of the electronic configuration of the iron atoms [12]. If we suppose that the recoilless fraction of the iron atoms is the same at every crystal site, the Cu occupation preference is calculated by Eq.…”

Preparation of Si–C–N–Fe magnetic ceramics from iron‐containing polysilazane

“…It is observed that the signals of their counterpart PSZIs shift 4±8 ppm to lower magnetic field. From the 29 Si and 1 H NMR of the PSZI-3 and PSZI-4, the Vi and Si-H contents decrease considerably, which might result from the reactions shown in Scheme 2 (n-BuLi and FeCl 3 might promote these reactions). The SiN-1, SiN-2, SiN-3, and SiN-4 samples are transparent liquids and can be easily dissolved in common .0 and 16.9 respectively.…”

“…For the 29 Si NMR of SiN-2 ( Fig. 2), signals in the range d À 3.8 to À8.1 are assigned to HN-SiMe 2 -NH, and d À 21 to À22.4 are assigned to (HN) 3 -SiMe; for the 29 Si NMR of SiN-3 (Fig. 2), signals in the range d À 3 to À7 are assigned to HN-SiMe 2 -NH, and d À 33 is assigned to (HN) 3 -SiVi.…”

“…1) appear, which may result from the formation of Si-N-Fe bonds. For the 29 Si NMR of SiN-2 ( Fig. 2), signals in the range d À 3.8 to À8.1 are assigned to HN-SiMe 2 -NH, and d À 21 to À22.4 are assigned to (HN) 3 -SiMe; for the 29 Si NMR of SiN-3 (Fig.…”