Study of NiFe2O4 nanoparticles using Mössbauer spectroscopy with a high velocity resolution

Abstract

The nanocrystalline NiFe 2 O 4 particles prepared by solution combustion synthesis technique using different fuels such as ethylene-diamine-tetra-acetic acid (NA sample) and urea (NB sample) were studied using magnetic measurement and 57 Fe Mössbauer spectroscopy with a high velocity resolution. The temperature dependence of magnetization is different for the two samples. Mössbauer spectra demonstrate the necessity to use more than two magnetic sextets, usually used to fit the NiFe 2 O 4 nanoparticles spectra. Evaluation of the different local microenvironments for Fe in both tetrahedral (A) and octahedral (B) sites, caused by different Ni 2+ occupation of octahedral sites, demonstrates at least five different local microenvironments for both A and B sites. Therefore, the Mössbauer spectra were fitted by using ten magnetic sextets which are related to the spread 57 Fe location in octahedral and tetrahedral sites.

Spinel Ferrite Nanoparticles: Correlation of Structure and Magnetism

“…Most works report the dominance of surface spin frustration and suggest the presence of the magnetically dead layer. The increased contribution of the frustrated spins is attributed mainly to size effect, low crystallinity, and surface roughness, dominating in the NPs obtained by coprecipitation method [26,[155][156][157][158][159][160][161][162][163][164][165]. The spin canting in the surface layer was also observed in diluted ferrofluids, which confirms the nature of the effect on single-particle level [166].…”

Study of Dronino Iron Meteorite Weathering in Clay Sand Using Mössbauer Spectroscopy

“…An analysis of components 1 -5 in the Mössbauer spectrum of the internal oxidation products in Dronino fragment № 1 (Figure 3a) on the basis of previously published data on iron oxides and hydroxides (see, for instance [11][12][13][14][15][16] ) permitted us to distinguish components 1, 3 and 2, 4, 5 and assigned these components to maghemite and magnetite, respectively. [17,18]). Other magnetic sextets 6 -8 were associated with goethite small particles with different size and smaller values of Heff than that for bulk -FeOOH (the Néel temperature is 400 K 16 ).…”

Study of Chelyabinsk LL5 meteorite fragment with a light lithology and its fusion crust using Mössbauer spectroscopy with a high velocity resolution

“…Based on the results of XRD study, these components were related to magnesioferrite which may be a product of combustion of silicate phases. [20,21]). Taking into account the difference between values for magnetic sextets 1 and both 2 and 3, we related component 1 to the 57 Fe in (A) sites while components 2 and 3 were related to the 57 Fe in [B] sites (see Table 1).…”