Effect of Cobalt Dopant on the Structural, Magnetic and Dielectric Properties of Fe3O4 Nanoparticles Prepared by Co-precipitation Method

Azab, A. A.; El-Menyawy, E.M.

doi:10.1007/s11664-019-07086-w

Cited by 12 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, the value of dielectric permittivity initially increases as temperature rises to 313 K due to thermally activated dipoles, increasing the electron exchange interaction which results in the increase of dielectric permittivity. Here, the obtained value of dielectric permittivity at room temperature is found to be comparatively higher than the reported ones [37][38][39][40]. The reason for such a high dielectric permittivity is that the prepared sample has electrical inhomogeneity caused by the G s and GBs effect.…”

contrasting

confidence: 54%

“…Here, the obtained value of dielectric permittivity at room temperature is found to be comparatively higher than the reported ones. [37][38][39][40] The reason for such a high dielectric permittivity is that the prepared sample has electrical inhomogeneity caused by the G s and GBs effect. Above 313 K, a decrease in the value of dielectric permittivity is observed due to the delocalization of conducting channels.…”

Section: Ac Conductivitymentioning

confidence: 99%

See 1 more Smart Citation

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

et al. 2022

View full text Add to dashboard Cite

show abstract

contrasting

confidence: 54%

Section: Ac Conductivitymentioning

confidence: 99%

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Decrement in values of Ms with Cr 3+ ions content can be interpreted according to theory of Neel's two sub-lattice model of ferrimagnetisms [46][47][48]. For ferrites, a net magnetization resulted from the uncompensated electron spin and spin alignments of an individual ions in octahedral B-sites which it anti-parallel to those in tetrahedral A-sites [49,50].According to Neel's model, A-B super-exchange interactions prevail B-B and A-A exchange interactions [51].Where Cr 3+ ions preferentially occupy octahedral B sites [52],so, substitution of highly magnetic moment Fe 3+ (5 μB) located in octahedral sites by lower magnetic moment Cr 3+ (3 μB) ions resulting a decreasing in net magnetization as well as the exchange interactions of sublattices. Fig.…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Impact of Chromium Doping on Structural, Optical, Magnetic and Electrical Properties of Nano-Copper Ferrite

GAD¹,

MOUSTAFA²,

AZAB³

et al. 2020

JOR

View full text Add to dashboard Cite

Nanoparticles copper ferrites doped with chromium CuCrxFe2- xO4 (0≤x≤ 0.25) were prepared using sol-gel auto combustion. Analysis of XRD revealed that the samples crystallized in single phase tetragonal CuFe2O4 structure. Results of Rietveld refinement using Full proff program showed that the lattice parameter a increased, lattice parameter c, the unit cell volume and tetragonal distortion decreased with increasing Cr3+ concentration. A cation distribution ensured that a system (CuCrFeO4) is completely inverse and distorted. In addition, crystallite size increased with the increase of Cr3+content.Furthermore, optical energy band gap of the obtained spinel ferrite decreased from 2.441eV to 2.228 eV with the increase of Cr. Results of magnetic properties indicated that the saturation magnetization decreased from 24.1 to18.3 emu/g with Cr increment, due to a lower magnetic moment of Cr3+ ion (3mB) than that of Fe3+ ion (5mB).Coercivity decreases with increasing Cr-concentration can be attributed to the reduction in magnetocrystalline anisotropy (K) where, chromium ferrite has negative magnetocrystalline anisotropy. Squareness ratio decreased continuously with Cr content, which it displayed that the materials exhibited to soft magnetic properties. Dielectric properties were analyzed in frequency range (0.1-7MHz) at different temperatures (50- 150ºC).From electrical measurements, it was found that έ decreased at lower frequency, become nearly constant at higher frequencies for all samples and increased with increasing temperature. έ was found to increase with increasing Cr because the Cr is reducing the hopping probabilities across the grain boundaries. . Also, it was found that activation energy ΔE decreased with increasing Cr concentration.

show abstract

“…Among the magnetic nanoparticles, cobalt ferrite (CoFe 2 O 4 ) has high electromagnetic performance [11], excellent chemical stability, mechanical hardness, and high cubic magneto-crystalline anisotropy [12]. These characteristics of the ZnO/CoFe 2 O 4 nanocomposite make it an attractive choice for a variety of commercial electronics applications, including video, audiotapes, high-density digital recording media, and magnetic fluids [13][14][15][16][17]. Nanocomposite materials have emerged as suitable alternatives to overcome the limitations of the physical properties of compounds.…”

Section: Introductionmentioning

confidence: 99%

Tailoring ZnO/CoFe₂O₄ nanocomposites: structure, optical, dielectric and magnetic study

Mahdy¹,

Azab²,

Zawawi³

et al. 2022

Phys. Scr.

Self Cite

View full text Add to dashboard Cite

The structural, morphology, optical, magnetic and dielectric properties of the (ZnO)1–x(CoFe2O4)x, (x= 1, 3 and 5 wt.%) nanocomposites synthetized by sonomechanical method were investigated using XRD, FE-SEM, HR-TEM, UV-visible, VSM and BDS. XRD analysis shows that, ZnO and CoFe2O4 acquired hexagonal and cubic phases, respectively. The optical band gap was reduced from 3.22 eV for pure ZnO to 3.15 eV after adding 5wt % of CoFe2O4. Addition of 1wt% CoFe2O4 to ZnO matrix showed a noticeable ferromagnetic behavior that was predominant in the prepared nanocomposites and confirmed by the convex Arrott–Belov–Kouvel curves. The dielectric constant, , at higher frequencies of the investigated nanocomposites is relatively high (8-10) accompanied by low values of dielectric loss,  ranging between 0.001 and 0.003 and hence very low values of the dissipation factor D (= /) making them applicable in the field of microwave shielding. On the other hand, the dc-conductivity, dc at 25 C shows a remarkable increase by Addition of 1wt% CoFe2O4 to ZnO matrix and decreases gradually with further increase of the ferrite. This indicates the effect of mobility and/or the number density of charge carriers on the conductivity. The investigation at higher temperature, 150 C, shows a gradual decrease in the conductivity with increasing CoFe2O4 content.

show abstract

Effect of Cobalt Dopant on the Structural, Magnetic and Dielectric Properties of Fe3O4 Nanoparticles Prepared by Co-precipitation Method

Cited by 12 publications

References 47 publications

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

Impact of Chromium Doping on Structural, Optical, Magnetic and Electrical Properties of Nano-Copper Ferrite

Tailoring ZnO/CoFe₂O₄ nanocomposites: structure, optical, dielectric and magnetic study

Contact Info

Product

Resources

About

Effect of Cobalt Dopant on the Structural, Magnetic and Dielectric Properties of Fe3O4 Nanoparticles Prepared by Co-precipitation Method

Cited by 12 publications

References 47 publications

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe3O4 nanoparticles

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe3O4 nanoparticles

Impact of Chromium Doping on Structural, Optical, Magnetic and Electrical Properties of Nano-Copper Ferrite

Tailoring ZnO/CoFe2O4 nanocomposites: structure, optical, dielectric and magnetic study

Contact Info

Product

Resources

About

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

Unusual semiconductor–metal–semiconductor transitions in magnetite Fe₃O₄ nanoparticles

Tailoring ZnO/CoFe₂O₄ nanocomposites: structure, optical, dielectric and magnetic study