Magnetic Properties of Co and Ni Substituted ɛ-Fe3N Nanoparticles

Abstract

In the present work, the nanostructured pseudo-binary ε-Fe 3−x CoxN and ε-Fe 3−x NixN (x = 0.0-0.8) systems (10-20 nm) are studied in detail for their intrinsic magnetic properties. These systems are indexed based on the hexagonal ε-Fe 3 N phase with the space group P6 3 /mmc. However, for the cobalt containing samples, x = 0.4-0.8, a mixture of hexagonal ε-Fe 3−x CoxN and bcc α-Fe phases are formed and for the nickel containing systems, x = 0.5-0.8, small amount of cubic γ -Fe 4−y NiyN is precipitated and these facts are supported by X-ray diffraction and 57 Fe Mössbauer spectroscopy studies. Mössbauer studies also confirm the random occupation of the substituent elements and the superparamagnetic nature of these particles. The intrinsic magnetic properties (σ s , T c ) are observed to vary with the Co and Ni contents. The low temperature magnetic properties are dominated by exchange bias phenomena and spin-glass like ordering, for these compositions.

Iron Nitride Family at Reduced Dimensions: A Review of Their Synthesis Protocols and Structural and Magnetic Properties

“…For ε-Fe 2.6 Ni 0.4 N NPs, the fitted parameters τ 0 = 10 –8 s and zν = 4.5 confirmed the existence of a spin glass phase (Figure a). Cobalt doping in ε-Fe 3 N could be obtained up to high atomic %, and in ε-Fe 2.4 Co 0.6 N NPs, the spin freezing process was speculated from the flattening of FC magnetization below 25 K …”

“…Ni could be doped in the ε-Fe 3 N lattice only up to 40 atomic %. 131,185,193,194 Higher Ni doping results in the precipitation of a small fraction of FM γ′-Fe 4−y Ni y N along with the major superparamagnetic ε-Fe 3−x Ni x N phase. 195 In γ′-Fe 4−y Ni y N, the added Ni atoms preferentially substitute the Fe (I) sites, where the isomer shift, quadrupole splitting, and hyperfine field vary with the Ni content.…”

High‐Pressure High‐Temperature Synthesis of ϵ‐Fe2IrN0.24

“…After estimating the formation energies of hypothetical compounds γ′‐ M Fe 3 N ( M refers to a transition metal of group 8, 9, or 10 of the periodic table of the elements) by means of total‐energy density functional calculations,5 the synthesis of a new predicted rhodium iron nitride γ′‐RhFe 3 N has been accomplished 6. In contrast, the knowledge about metal‐substituted ϵ‐Fe 3 N phases is much smaller: nano‐sized powders ϵ‐Fe 3– x Co x N, ϵ‐Fe 3– x Ni x N (0 ≤ x ≤ 0.8), and ϵ‐Fe 3– x Cr x N (0 ≤ x ≤ 0.2) have been synthesized and the interplays of transition‐metal identity, degree of substitution, and magnetic properties have been studied 7. By means of high‐pressure high‐temperature treatments, the metastable bulk nitrides ϵ‐Fe 2 CoN and ϵ‐Fe 2 NiN have recently been prepared and characterized 8…”

Magnetic and Mössbauer studies on nanocrystalline Co1−x Li x Fe2O4 (x = 0, 0.2)

“…It means that the formula of composition will be (Co 0. 8 Figure 3 shows the room temperature Mössbauer spectra of Co 1− x Li x Fe 2 O 4 (x = 0.0, 0.2). The sextet peaks are more asymmetric compared to that in liquid nitrogen temperature and also an additional unresolved broad contribution is seen clearly in the spectrum and the parameters are given in Table 2.…”