Magnetic properties of single domain ε-Fe3N synthesized by borohydride reduction route

Abstract

Single domain ε-Fe3N nitride particles have been synthesized by chemical reduction followed by nitridation at 823 K. The ε-Fe3N phase crystallizes in hexagonal structure with unit cell parameters, a=2.70 Å and c=4.39 Å. There is a reduction of unpaired d electrons for intraband polarization as the nitrogen contributes to the density of states and thus results in lowering of magnetic moments. The reduction of intrinsic magnetizations and Curie temperatures with decreasing particle size is attributed to canted spin structure predominantly at the surface compared to the bulk of the particles. Chemisorption of oxygen results in the formation of oxynitride layer at the surface with a ferromagnetic coupling to the spins in the core of the particle. Mössbauer study of ε-Fe3N particles exhibits the coexistence of ferromagnetic and superparamagnetic particles and corroborates the observed magnetic properties.

Frequency dispersion of complex permeability and permittivity on iron-based nanocomposites derived from rare earth-iron intermetallic compounds

“…Therefore, a two-phase ␣-Fe/Y 2 O 3 composite powders can be obtained by oxidizing ␣-Fe/YH 2 at the temperature around 523 K. After the nitrogenation in NH 3 at 623 K for 7 h, the XRD pattern of -Fe 3 N/Y 2 O 3 composites was measured as shown in Fig. 1(d), where not only the peaks of Y 2 O 3 and -Fe 3 N were clearly observed, but also the intensity sequence for the peaks of -Fe 3 N agreed with the previous result reported by Panda and Gajbhye [12]. Nitrogen contents of the resultant -Fe 3 N x /Y 2 O 3 composite powders were analyzed to be 6.23 wt%, which was correspondent to the composition of stoichiometric -Fe 3 N (x = 1).…”

Magnetic properties of ε ‐Fe 3–x Ni x N nanoparticles

“…Hence the saturation magnetization was found less at 300 K as compared to 5 K. The observed decrease of the 5 K temperature σ s value (10.32 emu/g) of ε-Fe 3 N as compared to the literature bulk value of 123.0 emu/g may be due to the canted spin structure, spin noncollinearity at the surface and most likely oxide layer at the surface of the nanoparticles. The contribution of the magnetic moment in the ε-Fe 3 N system is due to the unbalanced charge distribution between spin-up and spin-down states [10]. As Ni atoms randomly replace the Fe atoms in ε-Fe 3-x Ni x N, there exists an exchange interaction between the Fe 3d and Ni 3d states and the N 2p states.…”

Phase-dependent distribution of Fe-rich nanocrystals in MOVPE-grown (Ga,Fe)N

“…3b and from the FFT of Fig. 3c it is calculated that the d-spacing of the nanocrystal planes along the growth orientation is 0.214 nm and corresponds to the (0 0 0 2) planes of e-Fe 3 N [12].…”