Abstract:Cobalt ferrite (CoFe 2 O 4 , CFO) nanoplatelets with a rhomboidal shape were synthesized through a facile hydrothermal route using a very low concentration precursor at low temperatures. The effects of reaction temperature and time on the morphologies as well as the sizes of the products were systemically investigated. The as-synthesized CFO nanocrystals showed a special rhomboidal shape with crystal growth along the (111) direction. The very low concentration precursor plays an important role in forming CFO n… Show more
“…The low-frequency mode at 482 cm −1 is assigned as the vibrations of the octahedral sublattice, whereas the high energy phonon mode at 701 cm −1 originates from vibrations of the tetrahedral sublattice. 27 The …”
Section: A X-ray Diffraction Study (Xrd)mentioning
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
“…The low-frequency mode at 482 cm −1 is assigned as the vibrations of the octahedral sublattice, whereas the high energy phonon mode at 701 cm −1 originates from vibrations of the tetrahedral sublattice. 27 The …”
Section: A X-ray Diffraction Study (Xrd)mentioning
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
“…The results demonstrate a good single-phase magnetic behavior, and the magnetization changes smoothly with the applied field, which suggest that the soft and hard magnetic phase exchange coupled strongly [8,25]. Figure 5
Magnetic hysteresis loops and tendency of
M
s
and
H
c
of the samples.…”
Section: Resultsmentioning
confidence: 93%
“…Recently, a number of studies about the synthesis of CoFe 2 O 4 have been reported. CoFe 2 O 4 nanoparticles were fabricated by a sol-gel method by Xi et al [5], Mazario fabricated the CoFe 2 O 4 ferrite nanoparticles by an electrochemical method [6], CoFe 2 O 4 nanofibers was obtained by the electrospinning in 2009 [7], Liu et al prepared the CoFe 2 O 4 nanoplatelets using a facile hydrothermal route [8], and so on. However, the applications of CoFe 2 O 4 are often limited by its relatively low coercivity ( H c ).…”
Nanocomposite of CoFe2O4/SrFe12O19 has been synthesized by the electrospinning and calcination process. A novel method that cobalt powder was used to replace traditional cobalt salt in the precursor sol-gel for electrospinning was proposed. The crystal structures, morphologies, and magnetic properties of these samples have been characterized in detail. Moreover, when the average crystallite size of the hard/soft phases reached up to an optimal value, the CoFe2O4 have an enhanced saturation magnetization of 62.8 emu/g and a coercivity of 2,290 Oe. Significantly, the hysteresis loops for the nanocomposites show a single-phase magnetization behavior, and it has been found that the exchange coupling interaction strongly exists in the CoFe2O4/SrFe12O19 magnetic nanocomposite nanofibers.
“…It is important to notice that the Raman modes of the NiFe 2 O 4 nanoparticles annealed at lower temperature 200 o C are very broad and shift to low frequency as compared to that of nanoparticles annealed at higher temperature. This feature is related to a consequence of phonon confinement effect in nanocrystals [42][43].…”
Section: Field-emission Scanning Electron Microscopymentioning
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