Structural characterization and magnetic properties of undoped and copper-doped cobalt ferrite nanoparticles prepared by the octanoate coprecipitation route at very low dopant concentrations

Tedjieukeng, Hypolite Mathias Kamta; Tsobnang, Patrice Kenfack; Fomekong, Roussin Lontio; Etape, Ekane Peter; Joy, P.A.; Delcorte, Arnaud; Lambi, John Ngolui

doi:10.1039/c8ra08532c

Cited by 55 publications

(34 citation statements)

References 75 publications

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“…A simple strategy was developed by Wang et al [98], which consists of microwave-assisted coprecipitation of ferrous sulphate in a mixture of ethylene glycol and water, affording nanosheets with good crystallinity and saturation magnetization around 30 emu/g. Zhuang et al [99] were able to synthesize magnetite nanosheets through a solvothermal method using diethylene glycol, which, through the inhibition of the crystal plane (111), favours the formation of magnetite sheet-like crystals. Furthermore, the authors demonstrated that the nanoparticles self-assemble into chain-like structures along the direction of the external magnetic field, known as photonic crystals, which display a magnetochromatic property.…”

Section: Nano-films Sheets and Platesmentioning

confidence: 99%

“…Recently, Xu et al [110] were able to synthesize ultra-thin triangular magnetite nanoplates through a seed-mediated synthesis, where the seeds were obtained through the thermal decomposition of ferric oleate complex at 310 • C, and a growth-step (replenished with monomers) was carried out at a temperature (240 • C) lower than the required for nucleation (310 • C), but higher than the thermal decomposition of the complex (230 • C). Recently, the synthesis of Co 1-x Cu x Fe 2 O 4 has been achieved through a two-step synthesis, starting with coprecipitation of the metal salts in the right ratio, which dried powder was subjected to thermal decomposition in air at 400 • C in a tubular furnace [111]. Mn x Fe 1-x O nanoplates has also been recently reported, which are of biomedical interest owing to the resistance to oxidation in air compared to MnO and FeO, making them good candidates for magnetic contrast agents [112].…”

Section: Nano-films Sheets and Platesmentioning

confidence: 99%

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Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

130

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Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.

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Section: Nano-films Sheets and Platesmentioning

confidence: 99%

Section: Nano-films Sheets and Platesmentioning

confidence: 99%

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

130

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“…However, when x = 0.1, the copper ion present in the tetrahedral site has the lowest coercivity and highest value of magnetocrystalline anisotropy constant, which may be attributed to Jahn-Teller distortions induced by Cu 2+ ions in the spinel ferrite system [52,54,56]. The squareness ratio (SQR) was calculated using the given formula [57]:…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Tuning of Structural, Dielectric, and Electronic Properties of Cu Doped Co–Zn Ferrite Nanoparticles for Multilayer Inductor Chip Applications

et al. 2021

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Herein, we report the synthesis of nanoparticles and doping of Cu-doped Co–Zn ferrites using the auto-combustion sol–gel synthesis technique. X-ray diffraction studies confirmed the single-phase structure of the samples with space group Fd3m and crystallite size in the range of 20.57–32.69 nm. Transmission electron microscopy micrographs and selected area electron diffraction patterns confirmed the polycrystalline nature of the ferrite nanoparticles. Energy-dispersive X-ray spectroscopy revealed the elemental composition in the absence of any impurity phases. Fourier-transform infrared studies showed the presence of two prominent peaks at approximately 420 cm−1 and 580 cm−1, showing metal–oxygen stretching and the formation of ferrite composite. X-ray photoelectron spectroscopy was employed to determine the oxidation states of Fe, Co, Zn, and Cu and O vacancies based on which cationic distributions at tetrahedral and octahedral sites are proposed. Dielectric spectroscopy showed that the samples exhibit Maxwell–Wagner interfacial polarization, which decreases as the frequency of the applied field increases. The dielectric loss of the samples was less than 1, confirming that the samples can be used for the fabrication of multilayer inductor chips. The ac conductivity of the samples increased with increasing doping and with frequency, and this has been explained by the hopping model. The hysteresis loops revealed that coercivity decreases slightly with doping, while the highest saturation magnetization of 55.61 emu/g was obtained when x = 0.1. The magnetic anisotropic constant was found to be less than 0.5, which suggests that the samples exhibit uniaxial anisotropy rather than cubic anisotropy. The squareness ratio indicates that the samples are useful in high-frequency applications.

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“…The saturation magnetization, M s for all the compositions was obtained from the plot of M versus 1/H, for high H values, and extrapolating to 1/H = 0 (electronic supplementary material, figure S3) [38,39] It is observed that Co-substitution in NdFeO 3 greatly decreases the magnetization, coercive field, H c and remanent magnetization, M R . From the graph, the saturation magnetization of NdFeO 3 is 1.43 emu g −1 .…”

Section: Magnetic Properties By Vibrating Sample Magnetometermentioning

confidence: 99%

Effect of B-site Co substitution on the structure and magnetic properties of nanocrystalline neodymium orthoferrite synthesized by auto-combustion

et al. 2021

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Samples of cobalt-doped neodymium orthoferrite compounds, NdCo x Fe 1−x O 3 (0.0 ≤ x ≤ 0.5) were synthesized via glycine auto-combustion between 250 and 300°C and calcined at 500°C for 2 h. X-ray diffraction showed that all compounds had an orthorhombic perovskite structure with space group Pbnm. Increasing cobalt doping gradually reduced the lattice parameters and contracted the unit cell volume. Both X-ray diffraction and scanning electron microscopy showed that the particles were spherical and in the nano-sized range (19–52 nm) with pores between grains. Vibrating sample magnetometry at room temperature indicated that NdFeO 3 has a high coercive field (1950 Oe) and cobalt substitution for iron led to a decrease in the coercive field, saturation and remanent magnetization, which was as a result of decreased magnetic moments in the crystal and reduced canting of the FeO 6 octahedra. The increase in magnetization and coercive fields with increase of Co was connected to the microstructure (bond lengths and angles, defects, pores, grain boundaries) and crystallite size. The compounds NdCo x Fe 1−x O 3 show antiferromagnetism with weak ferromagnetism due to uncompensated non-collinear moments. These compounds could serve as prototypes for tuning the properties of magnetic materials (ferromagnetic and antiferromagnetic) with potential applications in data storage, logic gates, switches and sensors.

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Structural characterization and magnetic properties of undoped and copper-doped cobalt ferrite nanoparticles prepared by the octanoate coprecipitation route at very low dopant concentrations

Abstract: Low level copper-doped CoFe2O4 has been synthesized and shows an increasing of saturation magnetization up to 6% Cu, subsequently decreasing above 6%.

Cited by 55 publications

References 75 publications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Tuning of Structural, Dielectric, and Electronic Properties of Cu Doped Co–Zn Ferrite Nanoparticles for Multilayer Inductor Chip Applications

Effect of B-site Co substitution on the structure and magnetic properties of nanocrystalline neodymium orthoferrite synthesized by auto-combustion

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