Properties Of Ni-Zn Ferrite Nanoparticles Research Articles

Structural and Magnetic Properties of NiZn Ferrite Nanoparticles Synthesized by a Thermal Decomposition Method

Ni1−xZnxFe2O4 (x = 0.5, 0.6, 0.7) nanoparticles were synthesized by a thermal decomposition method. The synthesized particles were identified as pure spinel ferrite structures by X-ray diffraction analysis, and they were calculated to be 46–51 nm in diameter by the Scherrer equation, depending on the composition. In the FE-SEM image, the ferrite nanoparticles have spherical shapes with slight agglomeration, and the particle size is about 50 nm, which was consistent with the value obtained by the Scherrer equation. The lattice parameter of the ferrite nanoparticles monotonically increased from 8.34 to 8.358 Å as the Zn concentration increased from 0.5 to 0.7. Initially, the saturation magnetization value slowly decreases from 81.44 to 83.97 emu/g, then quickly decreases to 71.84 emu/g as the zinc content increases from x = 0.5, through 0.6, to 0.7. Ni1−xZnxFe2O4 toroidal samples were prepared by sintering ferrite nanoparticles at 1250 °C and exhibited faceted grain morphologies in the FE-SEM images with their grain sizes being around 5 µm regardless of the Zinc content. The real magnetic permeability (μ′) of the toroidal samples measured at 5 MHz was monotonically increased from 106, through 150, to 217 with increasing the Zinc content from x = 0.5, through 0.6, to 0.7. The cutoff frequency of the ferrite toroidal samples was estimated to be about 20 MHz from the broad maximum point in the plot of imaginary magnetic permeability (μ″) vs. frequencies, which seemed to be associated with domain wall resonance.

Influence of iron content on the structural and magnetic properties of Ni-Zn ferrite nanoparticles synthesized by PEG assisted sol-gel method

Ni-Zn ferrite nanoparticles of smaller particle size and high saturation magnetization have gained a special attention for their use in biomedical applications. The development of such nanoparticles requires rigorous processing conditions in arriving at desired characteristics. Ni-Zn ferrite nanoparticles of three different compositions Ni0.65Zn0.35Fe2O4, Ni0.65Zn0.40Fe1.95O4 and Ni0.60Zn0.35Fe2.05O4 containing varying amounts of iron concentration 50.00 mol%, 48.75 mol%, and 51.25 mol% respectively were processed by the sol-gel method using polyethylene glycol (PEG) as a chelating agent and characterized by techniques X-ray diffraction, Transmission electron microscopy, field emission scanning electron microscopy and Fourier transform infrared spectroscopy in elucidating the structural parameters. Ferrite compositions containing lower and higher iron content require the lower annealing temperature to produce higher saturation magnetization as compared to the stoichiometric composition. The composition of lower iron content favoured smaller particle size of 9 nm, while the material of higher iron content showed enhanced saturation magnetization of 91.9 emu/g. From the knowledge of literature and our previous works, it is opined that no other chelating agent than PEG proved to be an efficient one in controlling the particle size and improving the microstructure.

Structural and Electrical Properties of Ni-Zn Ferrite Nanoparticles: Influence of Mixed Fuel Approach

Structural and Electrical Properties of Ni-Zn Ferrite Nanoparticles: Influence of Mixed Fuel Approach

Influence of La3+ Substitution on Structure, Morphology and Magnetic Properties of Nanocrystalline Ni-Zn Ferrite.

Lanthanum substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5LaxFe1-xO4; 0.00 ≤x≤ 1.00) synthesized by sol-gel method were presented. X-ray diffraction patterns reveal the typical single phase spinel cubic ferrite structure, with the traces of secondary phase for lanthanum substituted nanocrystals. In addition, the structural analysis also demonstrates that the average crystallite size varied in the range of 21–25 nm. FTIR spectra present the two prominent absorption bands in the range of 400 to 600 cm-1 which are the fingerprint region of all ferrites. Surface morphology of both substituted and unsubstituted Ni-Zn ferrite nanoparticle samples was studied using FESEM technique and it indicates a significant increase in the size of spherical shaped particles with La3+ substitution. Magnetic properties of all samples were analyzed using vibrating sample magnetometer (VSM). The results revealed that saturation magnetization (Ms) and coercivity (Hc) of La3+ substituted samples has decreased as compared to the Ni-Zn ferrite samples. Hence, the observed results affirm that the lanthanum ion substitution has greatly influenced the structural, morphology and magnetic properties of Ni-Zn ferrite nanoparticles.

Structural, Optical and Magnetic Properties of Ni-Zn Ferrite Nanoparticles Prepared by a Microwave Assisted Combustion Method.

Ni-doped ZnFe₂O₄(Ni(x)Zn₁₋xFe₂O₄; x = 0.0 to 0.5) nanoparticles were synthesized by a simple microwave combustion method. The X-ray diffraction confirms the presence of cubic spinel ZnFe₂O₄for all compositions. The lattice parameter decreases with an increase in Ni content resulting in the reduction of lattice strain. High resolution scanning electron microscope images revealed that the as-prepared samples are crystalline with particle size distribution in 40-50 nm range. Optical properties were determined by UV-Visible diffuse reflectance and photoluminescence spectroscopy respectively. The saturation magnetization (Ms) shows the super paramagnetic nature of the sample for x = 0.0-0.2, whereas for x = 0.3-0.5, it shows ferromagnetic nature. The Ms value is 1.638 emu/g for pure ZnFe₂O₄ sample and it increases with increase in Ni content.

Effect of Aluminium Doping on Structural and Magnetic Properties of Ni-Zn Ferrite Nanoparticles

Aluminium doped Ni-Zn ferrite nanoparticles of general formula of Ni0.5Zn0.5AlxFe2-xO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0) have been synthesized by sol-gel auto combustion method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dis-persive X-ray (EDX), Fourier transform spectroscopy (FTIR) and vibrating sample magneto meter (VSM). XRD studies confirm that all compositions show single phase cubic spinel structure. The crystallite size was calculated using the Debye-Scherrer formula and found in the range of 17 - 52 nm. The lattice parameter “a” is found to decrease with increasing Al3+ content. The SEM images clearly show the crystalline structure and EDX patterns confirm the compositional formation of the synthesized compositions. The results of FTIR analysis indicated that the functional groups of Ni-Zn spinel ferrite were formed during the sol-gel synthesis process. The IR spectra showed two main absorption bands, the high frequency band ν1 around 600 cm-1 and the low frequency band ν2 around 400 cm-1 arising from tetrahedral (A) and octahedral (B) interstitial sites in the spinel lattice. As doping is increased the magnetic behavior is found to decrease and the composition x = 2.0 ferrite appears to be exhibiting superparamagnetism as the coercive field and retentivity are found near zero.

Electrical Properties of Ni-Zn Ferrite Nanoparticles Prepared by Simplified Sol-Gel Method

Ferrites have become the source of attention for scientists due to their variety of physical properties. Their massive use in the electronics industry has made the study of their dielectric, thermal, and optical properties unavoidable. These materials have potential applications in high-frequency devices. The empirical formula for the synthesized nanoparticles is given by Ni0.5Zn0.5Fe2O4. Nanoferrites were prepared by a simplified sol-gel method. The crystalline phase; crystallite size; surface morphology; dielectric properties such as AC conductivity (σAC), dielectric constant \((\epsilon ^{\prime })\), and dielectric loss (tan δ) as a function of frequency at different temperatures; and DC electrical resistivity as a function of temperature were studied. The Ni-Zn nanoferrite was sintered at 550 ∘C. The X-ray diffraction (XRD) results showed a spinel cubic structure having a lattice constant a=8.383 A and crystallite size of 12 nm for the (311) peak after sintering. Scanning electron microscopy showed the particle morphology of the samples. AC conductivity (σAC) increases with frequency as well as the temperature. DC resistivity decreased with increase in temperature. The observed behavior could be explained by the Maxwell-Wagner model. Parameters observed were correlated to understand the conduction mechanism.

Electromagnetic properties of NiZn ferrite nanoparticles and their polymer composites

The magnetic properties of polycrystalline NiZn ferrite nanoparticles synthesized using a polyol-reduction and coprecipitation reaction methods have been investigated. The effects on magnetization of synthesis approach, chemical composition, processing conditions, and on the size of nanoparticles on magnetization have been investigated. The measured room-temperature magnetization for the as-prepared magnetic nanoparticles (MNP) synthesized via polyol-reduction and coprecipitation is 69 Am2 kg−1 and 14 Am2 kg−1, respectively. X-ray diffraction measurements confirm spinel structure of the particles with an estimated grain size of ∼80 nm obtained from the polyol-reduction and 28 nm obtained from these coprecipitation techniques. Upon calcination under atmospheric conditions at different temperatures between 800 °C and 1000 °C, the magnetization, M, of the coprecipitated MNP increases to 76 Am2 kg−1 with an estimated grain size of 90 nm. The MNP-polymer nanocomposites made from the synthesized MNP in various loading fraction and high density polyethylene exhibit interesting electromagnetic properties. The measured permeability and permittivity of the magnetic nanoparticle-polymer nanocomposites increases with the loading fractions of the magnetic nanoparticles, suggesting control for impedance matching for antenna applications.

High-frequency magnetic properties of Ni-Zn ferrite nanoparticles synthesized by a low temperature chemical method

Spinel-structured Ni-Zn ferrite nanoparticles (NPs) have been directly synthesized by a low temperature co-precipitation method. The structure and high-frequency magnetic properties of the particles were investigated. The as-prepared Ni-Zn ferrite NPs demonstrate typical soft magnetic properties. The saturation magnetization ( M s), as high as about 60 emu/g, was achieved. The imaginary part μ ' ' of the permeability shows a broad peak in the frequency range 200 MHz~6 GHz, which indicates that the as-prepared Ni-Zn ferrite NPs have a remarkable feature of electromagnetic (EM) wave absorption in the high-frequency range. Hence, resultant Ni-Zn ferrite NPs can be used as efficient microwave absorbers and effective heating mediators for hyperthermia application in cancer therapy.

Structure and magnetic properties of NiZn ferrite nanoparticles

The physical and magnetic properties of NiZn ferrite nanoparticles have been determined. The particles were prepared by the wet method and dispersed as ferrofluids. Particles were prepared with 0.3Zn to 0.7Zn. Dry samples were used to investigate lattice parameters by X-ray diffraction. The physical particle sizes were measured by transmission electron microscopy and found to be typically 9 nm. Particle sizes were also determined by magnetic measurements and found to be around 5 nm, indicating a non-magnetic coating layer of about 4 nm. The Curie temperature was investigated for dry samples and found to decrease with the inverse square of the zinc content.