Influence of synthesis methods with low annealing temperature on the structural and magnetic properties of CoFe2O4 nanopowders for permanent magnet application

Abraime, B.; Maalam, K. El; Fkhar, L.; Mahmoud, Abdelfattah; Boschini, Frèdéric; Tamerd, Mohamed Ait; Benyoussef, A.; Hamedoun, M.; Hlil, E.K.; Ali, Mustapha Ait; Kenz, A. El; Mounkachi, O.

doi:10.1016/j.jmmm.2020.166416

Cited by 43 publications

(19 citation statements)

References 52 publications

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“…From the (BH) max versus H plot in Figure b, we have obtained the maximum value of 2.4 MGOe for C-2. To the best of our knowledge, this (BH) max product at room temperature exceeds the values previously reported for CoFe 2 O 4 . , We have compared the (BH) max value of C-2 with other reports, and a comparative analysis is presented in Table S3. ,− …”

Section: Resultsmentioning

confidence: 55%

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

2020

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Spinel ferrites, especially cobalt ferrite, have the capability of preserving sufficient magnetization (M s) and coercive field (H c). However, precise nanostructuring is needed to sustain the steady ferrimagnetic (FiM) response with high H c and remnant magnetization (M r). By a two-step process involving co-precipitation and inert calcination, CoFe2O4 nanoparticles (NPs) with inherent lattice strain were achieved with appreciable magnetic anisotropy. The disordered spins on the NP surface are found to be the key for maintaining the anisotropy and squareness (M r/M s) of hysteresis loops, the extent of which is a function of the processing temperature and NP size. The freezing of surface spins results in 2.8 and 1.2 nm thick spin glass (SG) layers for the as-prepared and 350 °C-calcined CoFe2O4 NPs, respectively, analyzed at 5 K. The frozen surface spins pin the core FiM spins, resulting in the exchange bias (H eb) coupling. At room temperature, 20 nm NPs exhibit permanent magnet-like features with a maximum energy product, BHmax, of 2.4 MGOe, which is quite promising considering CoFe2O4 as an environmentally friendly alternative to the hazardous rare-earth-based permanent magnets. Our CoF2O4 NP ensemble delivers both intriguing low-temperature magnetic properties having academic and technological interests and worthwhile room-temperature features that have direct translational relevance.

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Section: Resultsmentioning

confidence: 55%

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

2020

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“…Figure 1 show x-ray diffraction pattern for the synthesis of cobalt ferrite (CoFe 2 O 4 ) and trivalent ion-substituted cobalt ferrite (CoBi 0.1 Fe 1.9 O 4 , CoLa 0.1 Fe 1.9 O 4 and CoAl 0.1 Fe 1.9 O 4 ) as a result of coprecipitation at annealing temperature of 700 °C for 5 h. All peaks show hkl planes at (220), (311), (222), (400), (422), (511) and (440). XRD pattern analysis (ICDD 22-1086) of all samples confirmed the formation of a cubic spinel structure as the main characterization peak with the Fd-3m space group [13]. This is also confirmed in figure 2 which is the result of Rietveld refined patterns of CoFe 2 O 4 , CoBi 0.1 Fe 1.9 O 4 , CoLa 0.1 Fe 1.9 O 4 , and CoAl 0.1 Fe 1.9 O 4 nanoparticles, respectively.…”

Section: Results and Disscusionmentioning

confidence: 80%

“…For ferrite-based nanoparticles, the synthesis route has been introduced since a decade ago [6][7][8][9]. However, to date, it is still a fascination in materials research as fabrication technology advances in realizing theoretical results [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Cation trivalent tune of crystalline structure and magnetic properties in coprecipitated cobalt ferrite nanoparticles

Prasetya

Setiyani²,

Utari³

et al. 2023

Mater. Res. Express

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CoFe2O4, CoBi0.1Fe1.9O4, CoLa0.1Fe1.9O4, and CoAl0.1Fe1.9O4 nanoparticles were successfully synthesized by the coprecipitation method. After annealing at 700C for 5 h, the X-Ray Diffractometer results confirm that a single phase of cobalt ferrite-based nanoparticles is obtained, which is suitable for ICDD 22-1086. The addition of Bi3+, La3+ and Al3+ ions to the cobalt ferrite nanoparticles modified the crystallite size and lattice constant. Trivalent metal cation substitution tunes the crystallite size which has also been confirmed by measuring the grains with Scanning Electron Microscope images. In the Far Transform Infra-Red curve, the addition of metal ions (Bi3+, La3+, and Al3+) to cobalt ferrite nanoparticles resulted in absorption peaks at the tetrahedral and octahedral sites without any additional absorption peaks. The VSM results showed that saturation magnetization decreased drastically in the presence of trivalent non-magnetic cations, which confirms the replacement of Fe3+ by trivalent non-magnetic cations. The kOe order of the coercive field was obtained in this experiment. The largest coercive field of the cobalt ferrite nanoparticles was obtained with the addition of La3+ ions, i.e., 3.67 kOe suggest supporting both Jahn-Teller effect and strain-induced magnetism.

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“…The particle size with high magnetization values, as well as the loss of magnetization after removal of the magnetic field, is an important property of MNPs used for medical and environmental purposes [ 34 ]. Only the MNP-5 sample exhibited high hysteresis, indicating the presence of ferromagnetic properties [ 44 ]. Magnetic properties of ferrites are directly dependent on the divalent metals present in their composition [ 45 ], the synthesis methods and the corresponding preparation conditions.…”

Section: Resultsmentioning

confidence: 99%

Morphology-Controlled Green Synthesis of Magnetic Nanoparticles Using Extracts of ‘Hairy’ Roots: Environmental Application and Toxicity Evaluation

et al. 2022

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Magnetic nanoparticles (MNPs) were “green” synthesized from a FeCl3/FeSO4/CoCl2 mixture using ethanolic extracts of Artemisia tilesii Ledeb ‘hairy’ roots. The effect of chemical composition and reducing power of ethanolic extracts on the morphology, size destribution and other features of obtained MNPs was evaluated. Depending on the extract properties, nanosized magnetic materials of spherical (8–11 nm), nanorod-like (15–24 nm) and cubic (14–24 nm) shapes were obtained via self-assembly. Microspherical MNPs composed of nanoclusters were observed when using extract of the control root line in the synthesis. Polyhedral magnetic nanoparticles with an average size of ~30 nm were formed using ‘hairy’ root ethanolic extract without any additive. Studied samples manifested excellent magnetic characteristics. Field-dependent magnetic measurements of most MNPs demonstrated a saturation magnetization of 42.0–72.9 emu/g with negligible coercivity (∼0.02–0.29 emu/g), indicating superparamagnetic behaviour only for solids with a magnetite phase. The synthesized MNPs were minimally aggregated and well-dispersed in aqueous medium, probably due to their stabilization by bioactive compounds in the initial extract. The nanoparticles were tested for magnetic solid-phase extraction of copper (Cu), cadmium (Cd) and arsenic (As) pollutants in aqueous solution, followed by ICP-OES analysis. The magnetic oxides, mainly magnetite, showed high adsorption capacity and effectively removed arsenic ions at pH 6.7. The maximum adsorption capacity was ~150 mg/g for As(III, V) on the selected MNPs with cubic morphology, which is higher than that of previously reported adsorbents. The best adsorption was achieved using Fe3O4-based nanomaterials with low crystallinity, non-spherical form and a large number of surface-localized organic molecules. The phytotoxicity of the obtained MNPs was estimated in vitro using lettuce and chicory as model plants. The obtained MNPs did not exhibit inhibitory activity. This work provides novel insights on the morphology of “green” synthesized magnetic nanoparticles that can be used for applications in adsorption technologies.

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Influence of synthesis methods with low annealing temperature on the structural and magnetic properties of CoFe2O4 nanopowders for permanent magnet application

Cited by 43 publications

References 52 publications

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

Cation trivalent tune of crystalline structure and magnetic properties in coprecipitated cobalt ferrite nanoparticles

Morphology-Controlled Green Synthesis of Magnetic Nanoparticles Using Extracts of ‘Hairy’ Roots: Environmental Application and Toxicity Evaluation

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