Rietveld analysis of XRD patterns of different sizes of nanocrystalline cobalt ferrite

Kumar, Lawrence; Kumar, Pawan; Narayan, A.; Kar, Manoranjan

doi:10.1186/2228-5326-3-8

Cited by 256 publications

(115 citation statements)

References 38 publications

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“…We also determined the oxygen position to be (0.2505(2), 0.2505(2), 0.2505 (2)). These values are in agreement with the results reported by Baraliya and Joshi 22 and Kumar et al 23 The lattice constant is 1% larger than in the bulk material, which is a typical feature of CoFe 2 O 4 nanoparticles. 22,23 However, using the Scherrer's equation, 24 from the full width at hall maximum (FWHM) of peak (311), a mean grain size of 38(2) nm is obtained.…”

Section: A Sample Characterizationsupporting

confidence: 83%

Cobalt ferrite nanoparticles under high pressure

Saccone

Ferrari

Errandonea

et al. 2015

Journal of Applied Physics

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Articles you may be interested inMicrostructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method J. Appl. Phys. 117, 17A328 (2015) We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe 2 O 4 ) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20-27 GPa to 7.5-12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B 0 ¼ 204 GPa) is considerably larger than the value previously reported for bulk CoFe 2 O 4 (B 0 ¼ 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B 0 ¼ 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible. V C 2015 AIP Publishing LLC. [http://dx

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Section: A Sample Characterizationsupporting

confidence: 83%

Cobalt ferrite nanoparticles under high pressure

Saccone

Ferrari

Errandonea

et al. 2015

Journal of Applied Physics

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“…The small shift in the XRD patterns is observed at higher 2θ angle, when the Ni content in the product increases. This can be explained by the fact that the ionic radius (0.072 nm) of Ni 2+ ions is smaller than that (0.074 nm) of Co 2+ ions, 25 which corresponds to lower lattice parameter and lattice volume with the decrease in crystallite size. The average crystallite size was calculated from line broadening of XRD pattern (inset of fig.…”

Section: A X-ray Diffraction Study (Xrd)mentioning

confidence: 99%

Structural, dielectric and magnetic properties of nickel substituted cobalt ferrite nanoparticles: Effect of nickel concentration

et al. 2015

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Microstructure and magnetic properties of MFe 2 O 4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method Journal of Applied Physics 117, 17A328 (2015) Nickel substituted cobalt ferrite nanoparticles with composition Co 1−x Ni x Fe 2 O 4 (0.0≤x≤1.0) was synthesized using simple, low temperature auto combustion method. The X-ray diffraction patterns reveal the formation of cubic phase spinel structure. The crystallite size varies from 30-44 nm with the nickel content. Porous and agglomerated morphology of the bulk sample was displayed in the scanning electron microscopy. Micro Raman spectroscopy reveals continuous shift of E g and E g (2) stokes line up to 0.8 Ni substitution. The dispersion behavior of the dielectric constant with frequency and the semicircle nature of the impedance spectra show the cobalt nickel ferrite to have high resistance. The ferromagnetic nature is observed in all the samples, however, the maximum saturation magnetization was achieved by the 0.4 Ni substituted cobalt ferrite, which is up to the 92.87 emu/gm at 30K. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx

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“…The magnetic properties (such as saturation magnetization (M s ) and coercive field (H c ) of nanocrystalline Ca(MgTi) x Fe 12−2x O 19 ) have been performed by using a vibrating sample magnetometer at room temperature with maximum applied magnetic fields up 12,000 Oe. Microwave absorption properties measured by standingwave-ratio (SWR) method.…”

Section: Methodsmentioning

confidence: 99%

“…Lattice constant values, calculated using the standard Eq. [16,17], are given in 19 hexaferrite samples with different Mg-Ti contents. It illustrates that the particle size is nearly symmetrical and uniform.…”

Section: Crystal Structurementioning

confidence: 99%

“…But rarely has been investigated microwave absorption magnetic properties calcium hexaferrite [13,14] 19 (x = 0, 0.3, 0.6, 0.9) hexagonal ferrites (x = 0, 0.3, 0.6, 0.9) were synthesized by the citrate sol-gel method. The microwave absorption, crystal structure, magnetic and morphology of the nanopowders were investigated with vector network analyzer, X-ray diffraction (XRD), vibrating sample magnetometer and transmission electron microscopy.…”

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confidence: 99%

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