Mössbauer Study of Cobalt-Zinc Ferrites

Petitt, G.; Forester, D. W.

doi:10.1103/physrevb.4.3912

Cited by 245 publications

(90 citation statements)

References 32 publications

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“…Therefore, substitution of Cu by Zn in Cu 1-x Zn x Fe 2 O 4 is expected to modify the magnetic properties. The magnetization behavior and magnetic ordering of Zn-substituted Co-Zn [4], Cu-Zn [5], Ni-Zn [6], and Mg-Zn [7] ferrites have been studied by many authors. However, no detail works have been found in the literature regarding structural and hysteresis behavior of mixed Cu-Zn ferrite.…”

Section: Introductionmentioning

confidence: 99%

Structural phase transformation and hysteresis behavior of Cu-Zn ferrites

2013

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A series of Cu 1-x Zn x Fe 2 O 4 ferrite (with x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) compositions were synthesized using the standard solid-state reaction technique. X-ray diffraction was used to study the structure of the above investigated samples. The theoretical and experimental lattice parameters (a th and a exp ) were calculated for each composition. A significant decrease in density and subsequent increase in porosity were observed with increasing Zn content. Curie temperature, T C , has been determined from the temperature dependence of permeability and found to decrease with increasing Zn content. The anomaly observed in the temperature dependence of permeability was attributed to the existence of two structural phases: cubic phase and tetragonal phase. Low-field hysteresis measurements have been performed using a B-H loop trace from which hysteresis parameters have been determined. Coercivity and hysteresis loss were estimated with different Zn contents.

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Section: Introductionmentioning

confidence: 99%

Structural phase transformation and hysteresis behavior of Cu-Zn ferrites

2013

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“…Because of their relatively larger separation (~3.5 Å) the A-site cations are not expected to have detectable interactions with other Asite cations. In general, a B-site cation interacts though rather weakly with another B-site cation only by a direct overlap or through 90 o superexchange interaction [23]. The above depiction hints that the strongest oxygen mediated superexchange interaction is the A-O-B in comparison to the B-O-B and A-O-A arrangement.…”

Section: Magnetization Studiesmentioning

confidence: 95%

Effect of Sintering Temperature on the Micro Strain and Magnetic Properties of Ni-Zn Nanoferrites

Venkatesh¹,

Prasad²,

Babu³

et al. 2015

Journal of Magnetics

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In this study, nanocrystalline ferrite powders with the composition Ni 0.5 Zn 0.5 Fe 2 O 4 were prepared by the autocombustion method. The obtained powders were sintered at 800 o C, 900 o C and 1,000 o C for 4 h in air atmosphere. The as-prepared and the sintered powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and magnetization studies. An increase in the crystallite size and a slight decrease in the lattice constant with sintering temperature were observed, whereas microstrain was observed to be negative for all the samples. Two significant absorption bands in the wave number range of the 400 cm −1 to 600 cm −1 have been observed in the FT-IR spectra for all samples which is the distinctive feature of the spinel ferrites. The force constants were found to vary with sintering temperature, suggesting a cation redistribution and modification in the unit cell of the spinel. The M-H loops indicate smaller coercivity, which is the typical nature of the soft ferrites. The observed variation in the saturation magnetization and coercivity with sintering temperature has been attributed to the role of surface, inhomogeneous cation distribution, and increase in the crystallite size.

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“…[33] The site assignment, from the extent of hyperfine magnetic fields in CoFe2O4, is controversial in the literature. [33][34][35][36][37] More recent studies consider that the IS values correlated with the structural data can be better used for site assignments in cobalt ferrite. Consequently, the sextet with lower IS (~ 0.19 mm s -1 , relative to -iron) is assigned to iron in tetrahedral sites (from inter-nuclear distance arguments) [35] and the sextet with higher IS (0.32 mm s -1 ) corresponds to octahedral iron sites.…”

Section: Ft-ir Spectroscopymentioning

confidence: 99%

“…In order to understand the Mössbauer results we have to remember that in AB2O4 spinels every A-site (tetrahedral) iron ion is surrounded by 12 B-site (octahedral) next nearest neighbours and each B-site iron ion is bounded by six A-site nearest neighbours. [33,34] The hyperfine parameters (isomer shift IS, quadrupole splitting ΔEQ and magnetic fields Hhf at the iron nucleus) for all Mössbauer spectra are listed in Table 1. In the computer fit, the line intensities were fixed at 3 : 2 : 1 (theoretical values) for all magnetic sublattices, the line widths were considered equal and kept fixed for all magnetic sextets and free for the central quadrupole doublet.…”

Section: Ft-ir Spectroscopymentioning

confidence: 99%

Chromium Substituted Cobalt Ferrites by Glycine-Nitrates Process

Gingaşu¹,

Diamandescu²,

Mîndru³

et al. 2015

Croat. Chem. Acta

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Chromium substituted cobalt ferrites (CoFe2-xCrxO4, 0  x  2) were synthesized through solution combustion method using glycine as fuel, named glycine-nitrates process (GNP). As evidenced by X-ray diffraction data (XRD), single cubic spinel phase was formed for all CoFe2−xCrxO4 (0  x  2) series. The cubic lattice parameter (a) decreases with increasing chromium content. Room temperature 57 Fe Mössbauer spectra revealed the Fe 3+ and Cr 3+ site occupancy, the local hyperfine magnetic fields and the substitution of Fe 3+ by Cr 3+ in the lattice. Scanning electron microscopy (SEM) showed a refinement of particle size with the increase of Cr 3+ content. Magnetic measurements from 5 K to 120 K have shown a dropping in the saturation magnetization as the chromium content increases. This behaviour has been explained in terms of substitution of Fe 3+ by Cr 3+ in the cubic lattice of cobalt ferrite.

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Mössbauer Study of Cobalt-Zinc Ferrites

Cited by 245 publications

References 32 publications

Structural phase transformation and hysteresis behavior of Cu-Zn ferrites

Structural phase transformation and hysteresis behavior of Cu-Zn ferrites

Effect of Sintering Temperature on the Micro Strain and Magnetic Properties of Ni-Zn Nanoferrites

Chromium Substituted Cobalt Ferrites by Glycine-Nitrates Process

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