NiZn Ferrite Nanoparticles Research Articles

Influence of nickel addition on structural and magnetic properties of aluminium substituted Ni-Zn ferrite nanoparticles

Ni-Zn-Al mixed ferrite nanoparticles, with general formula NixZn1-xAlFeO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), were synthesized by sol-gel auto combustion technique. All prepared ferrite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometer. X-ray diffraction study confirmed the formation of the single phase cubic spinel structure in all ferrite samples. The crystallite size was calculated by the Debye-Scherrer formula and found to be in the range 15-46 nm. The lattice constant decreased with increasing Ni2+ ion concentration. Scanning electron microscopy images clearly indicate that the particles are very small but agglomerated. Energy dispersive X-ray was used to confirm the composition of the prepared powders. Fourier transform infrared spectra showed two main absorption bands of ferrite nanoparticles, the high frequency band (?1) around 600 cm-1 and the low frequency band (?2) around 400 cm-1 arising from tetrahedral (A) and octahedral (B) interstitial sites in the spinel lattice, respectively. Vibrating sample magnetometer results reported that the saturation magnetization, remanent magnetization and magnetic moments decrease with increasing Ni2+ion concentration.

Magnetic, electrical and microwave properties of Mn–Co substituted NixZn0,8-xFe2O4 nanoparticles

Mn–Co substituted spinel Ni–Zn ferrite nanoparticles were synthesized in the form of NixZn0,8-xMn0.1Co0.1Fe2O4 (0 ≤ x ≤ 0.8) using the solid state reaction route. 1 wt.% B2O3 (boron) was added to initial mixture to inhibit crystal growth. Structural characterization showed that single phase NiZn-ferrite nanoparticles were obtained upto the nickel concentration of x = 0.5 and above that a small fraction of hematite phase (α-Fe2O3) was detected. It was observed that ac conductivity of nanoparticles decreases with increasing nickel amount giving rise to better stability of electrical bonds between Ni and Fe ions. Besides, ac conductivity also decreases with decreasing frequency which is considered as a signature of an ionic conductivity. Magnetic measurements revealed that as nickel concentration increases up to x = 0.5, the saturation magnetization of the samples increases. Further increase results in a decrease in the magnetization. The microwave characterization showed that the samples of Ni0.6Zn0.2Mn0.1Co0.1Fe2O4 and Ni0.8Mn0.1Co0.1Fe2O4, have the best absorption properties with minimum reflection losses of −25 dB at 10 GHz and 12 GHz, respectively. The mechanism of absorption appears to be quarter wavelength cancellation at the matching thickness, which increases exponentially with decreasing microwave frequency.

Enhanced Saturation Magnetization in Cobalt Doped Ni-Zn Ferrite Nanoparticles

The Co substitution in Ni-Zn ferrites with respect to their structural and magnetic properties has been investigated in favor to select a material for future electromagnetic interference (EMI) shielding application purpose. Ni0.6−x Zn0.4Co x Fe2O4 (x = 0, 0.03, 0.09, 0.27) nanoparticles were synthesized using a sol-gel method and annealed at 700∘C. The prepared Ni0.6−x Zn0.4Co x Fe2O4 samples were characterized for their structural, stoichiometric, and magnetic properties. X-ray diffraction patterns reveal the formation of single-phase spinel cubic structure formed at x = 0.27. The influence of Co doping on structural properties of Ni-Zn ferrite was examined with X-ray diffraction and field emission scanning electron microscopy. The stoichiometry of prepared samples has also been examined by energy-dispersive X-ray spectroscopy. The magnetic behavior was studied using a vibrating sample magnetometer at room temperature. The variations in values of saturation magnetization were explained on the basis of spin canting effect imparted by hematite (α-Fe2O3) phase with spinel phase. Ni0.6−x Zn0.4Co x Fe2O4 with x = 0.27 possesses best saturation magnetization and can be useful in EMI shielding material.

Synthesis, characterization and dielectric properties of Polyaniline@Ni0.5Zn0.5Fe2O4 composite nanofibers

Polyaniline@Ni0.5Zn0.5Fe2O4 (PANI@NiZn) composite nanofibers were prepared by in situ polymerization of aniline in the presence of NiZn ferrite nanoparticles. The composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV–vis and FTIR spectra. Their magnetic and dielectric properties were found that the PANI@NiZn nanocomposite nanofibers possess adjusted magnetic properties by change NiZn content. The PANI@NiZn composite nanofibers also have high dielectric constant and exhibit two dielectric relax regions at room temperature. The high-frequency dielectric relaxtion at about 3.5MHz may be contribute to the interfacial polarization occuring at the interface of NiZn nanoparticle and PANI polymer. This will reach a better understanding of the mechanism in polymer/inorganic nanocomposites.

Investigation of Some Magnetic and Thermal Properties of $$\hbox {Epoxy/Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}$$ Epoxy/Ni 0.5 Zn 0.5 Fe 2 O 4 Composites

Nanoparticles of \(\hbox {Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}\) have been prepared by the co-precipitation method, and X-ray diffraction analysis has confirmed the formation of the desired ferrite. A pure epoxy sample and three samples of \(\hbox {epoxy/Ni}_{0.5}\hbox {Zn}_{0.5}\hbox {Fe}_{2}\hbox {O}_{4}\) composites have also been prepared with different ferrite percentages. These samples have been characterized by Fourier transform infrared spectroscopy. The magnetization of the composites has been investigated by using a vibrating sample magnetometer and has revealed that these composites may be promising candidates for electromagnetic interference suppression. Moreover, the thermal diffusivity and thermal effusivity of epoxy and composite samples have been measured by using the photoacoustic technique, where a high enhancement of the thermal diffusivity with increasing ferrite content has been observed which can be attributed to the higher number of phonon vibrational modes as well as the longer mean free path of the ferrite nanoparticles due to their crystalline structure as compared to the amorphous structure of epoxy. Moreover, the formation of a percolated network of NiZn ferrite nanoparticles inside the epoxy may enhance the phonon conduction, increasing the value of the thermal diffusivity in the bulk of the samples. On the other hand, the almost constant values of the thermal effusivity—which is a surface property—suggest that these composites may be used not only for electromagnetic interference suppression but also for thermal shielding in electronic circuits.

Effect of NiZn Ferrite Nanoparticles upon the Structure and Magnetic and Gyromagnetic Properties of Low-Temperature Processed LiZnTi Ferrites

NiZn ferrite nanoparticles (2–20 wt %) of composition Ni0.4Zn0.6Fe2O4 were introduced into LiZnTi ferrite of composition Li0.42Zn0.27Ti0.11Fe2.2O4 and sintered at a temperature of 920 °C for 2 h, well below that of the Ag melting point. Here, LiZnTi ferrites were prepared by a solid-state reaction method, and NiZn ferrite nanoparticles were fabricated by a hydrothermal chemical technique at 180 °C. A low ferromagnetic resonance (FMR) line width, low coercivity, and high magnetic moment were achieved after refinement of the heat treatment conditions of the mixture. Riveted full profile refinement of the X-ray powder diffraction patterns and analysis of Mossbauer spectra were employed to study the structure and caption distribution. The results confirm a pure spinel phase after processing. A narrow FMR line width of 152.5 Oe, a reduced coercivity of 132.9 A/m, and an improved saturation magnetization of 74.23 emu/g were obtained by way of the addition of 8 wt % NiZn ferrite nanoparticles.

Effect of Pr3+ substitution on the microstructure, specific surface area, magnetic properties and specific heating rate of Ni0.5Zn0.5PrxFe2−xO4 nanoparticles synthesized via sol–gel method

A series of Ni–Zn ferrite nanoparticles with a nominal composition of Ni0.5Zn0.5PrxFe2−xO4 (x=0.000–0.100 with steps of 0.025) has been synthesized by a sol–gel method. The effect of composition and calcination temperature on the morphology, specific surface area, magnetic properties and specific heating rate has been studied. The Ni–Zn–Pr ferrites have a single spinel (NZF) phase at Pr loadings below 5at%. A minor amount of an orthorhombic PrFeO3 phase is present in the Ni–Zn–Pr ferrites at Pr loadings above 5at%. At a Pr loading of 10at%, the specific surface area increases six-fold as compared to that of the non-doped Ni0.5Zn0.5Fe2O4 sample. As the Pr loading increases, the saturation magnetization, remnant magnetization and coercivity increase and reach the maximum at x=0.05 and then decrease. The maximum values of these parameters are 67.0emu/g, 9.7emu/g and 87.2Oe, respectively. Under radiofrequency field (frequency: 295kHz, intensity: 500Oe), the highest heating rate of 1.65K/s was observed over the sample with x=0.025 which is 2.5 times higher than that of Ni0.5Zn0.5Fe2O4.

Structural and magnetic properties of Cr doped NiZn-ferrite nanoparticles prepared by surfactant assisted hydrothermal technique

In this research paper, we report synthesis of nanocrystalline ferrite materials with a general formula Ni0.5Zn0.5CrxFe2–xO4 (x=0.0, 0.3) by the surfactant (PEG) assisted hydrothermal method and a systematic investigation on the structural, compositional and magnetic properties of undoped and Cr3+ doped NiZn-ferrite nanoparticles. The structural, compositional and magnetic properties of prepared samples were investigated using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometry (VSM). The XRD analysis of the synthesized samples confirmed the formation of single-phase cubic spinel structure and the average crystallite sizes of the nanoparticles were estimated using Debye–Scherrer׳s equation as 12.16nm and 12.11nm for undoped and Cr doped samples, respectively. The results of FT-IR analysis indicated that the functional groups of Ni–Zn spinel ferrite were formed during the hydrothermal synthesis process. Moreover, FE-SEM micrographs demonstrated that nanoparticles with narrow size distribution and without agglomeration were obtained. Magnetization measurements have shown that the particles have superparamagnetic behavior at high temperatures and ferrimagnetic behavior with relatively small coercive fields at low temperatures. The hysteresis curves of the samples exhibited the reduction of saturation magnetization and coercivity by Cr3+ ions substitution. Magnetization and the coercive field of the samples increase by decreasing the temperature. The blocking temperature TB is also decreased by Cr doping. The presence of superparamagnetism with very small coercivity (soft ferrite) indicating the samples are good candidates for applications in high-frequency transformers.

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.

Effects of Dy3+ substitution on the structural and magnetic properties of Ni0.5Zn0.5Fe2O4 nanoparticles prepared by a sol-gel self-combustion method

A series of Ni-Zn ferrite nanoparticles with a nominal composition Ni0.5Zn0.5DyxFe2-xO4 (x=0.000–0.100 with steps of 0.025) was prepared by a simple sol-gel self-combustion method. The effects of composition and calcined temperatures on their morphology, specific area, magnetic properties and radio frequency heating rate are studied. It is found that all the Dy3+ substituted Ni-Zn ferrites exhibit typical spinel structure. Moreover, Dy3+ substitution can notably reduce the average crystal size and enhance the specific area of Ni-Zn ferrite. The value of specific area reaches 29.25m2/g when x is 0.1, about five times higher than that of Ni0.5Zn0.5Fe2O4 sample. With the increase of Dy3+ content, all the values of Ms, Mr and Hc increase first and then decrease, and they maximize to 67.801emu/g (Ms), 11.10 (Mr) and 79.89G (Hc), improving about 28%, 208% and 92%, respectively, compared with those of Ni0.5Zn0.5Fe2O4, when calcined at 1073K and x is 0.025. In addition, the heating rate of Dy-substituted samples are also enhanced markedly.

Magnetocaloric effect in Ni-Zn ferrite nanoparticles prepared by using solution combustion

Ni x Zn1−x Fe2O4 (x = 0.2 and 0.3) ferrite nanoparticles with sizes ranging from 65 to 70 nm were synthesized employing the solution combustion route. The magnetocaloric behavior was investigated within the 50 K ≤ T ≤ 400 K range of temperatures (T). The entropy change (ΔS) and the adiabatic temperature change (ΔT) were derived from magnetization (M) and specific heat (C P ) measurements. Both compositions exhibited broad peaks for the isothermal entropy change. The magnetic field (H)-dependent ΔT was analyzed within the mean-field approximation scheme, and the observed magnetocaloric properties of the nanoparticle samples were compared with those of a bulk sample. Our study suggests that the magnetocaloric properties of magnetic oxides strongly depend on the particle size; thus, particle size should be considered as a key tuning parameter in the optimization of magnetic refrigeration.

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.

Improving the Economic Values of the Recycled Plastics Using Nanotechnology Associated Studies

Recycled polystyrene (PS) cups were chopped up and separately incorporated with multiwall carbon nanotubes (MWCNTs) and NiZn ferrite (Ni0.6Zn0.4Fe2O4) nanoparticles prior to electrospinning under different conditions. These nanoscale inclusions were initially dispersed well in dimethylformamide (DMF), and then known amounts of the recycled PS pieces were added to the dispersions prior to 30 min of sonication followed by 4 h of high-speed agitation at 750 r/min. The thermal, dielectric, surface hydrophobic, and magnetic properties of the resultant nanocomposite fibers were determined by thermal comparative, capacitance bridge, vibrating sample magnetometer (VSM), and goniometer techniques, respectively. Test results confirmed that the physical properties of recycled nanofibers were significantly increased as a function of the inclusion concentrations, which may be because of their excellent properties. The consumption of polymeric products as well as their waste materials has dramatically grown worldwide. Although plastic recycling, reprocessing, and reusing rates are growing, the physical properties and economic value of recycled plastics are significantly low. Consequently, this work provides a detailed explanation of how to improve recycled plastics, making them into highly valued new nanoproducts for various industrial applications, including filtration, textile, transportation, construction, and energy.

Size controlled preparation of Fe–B–P submicrometre particles and magnetic performance

Fe–B–P submicrometre particles were synthesised by a novel chemical method. The size of the Fe–B–P particles (0·1–1 μm) is easily controlled by tuning the NaBH4 concentration and its dropping speed. The saturation magnetisation (Ms) of Fe–B–P submicrometre particles is >130 emu g−1, whereas the coercivity is <10 Oe. The permeability of the composites made of Fe–B–P particles (∼0·3 μm) and NiZn ferrite nanoparticles (10 nm) is ∼25 when the volume percentage of NiZn ferrite is 30–50%. The resonance frequencies are all ∼1 GHz for pure Fe–B–P particles and the composites.

Shape and size-controlled synthesis of Ni Zn ferrite nanoparticles by two different routes

Monodisperse Ni–Zn ferrite nanoparticles of different compositions have been synthesized using two different routes, such as sonochemical and polyol methods. In both the cases, the process was attempted in a single reaction in the absence of any surfactant and deoxygenated conditions. X-ray diffraction data on the samples confirmed formation of pure ferrite phase with spinel structure, and indicated that the sonochemical method produces highly crystalline particles compared to the polyol process. Transmission electron microscopy images reveal formation of different shapes, such as cubic, spherical, flower-like and amorphous depending on the method and composition of the ferrite. The magnetic properties of the synthesized Ni–Zn ferrite nanoparticles, measured by vibrating sample magnetometer at room temperature, show that the highest magnetization value was obtained for the composition of Ni0.5 Zn0.5 Fe2O4 in both the synthesis methods. The results of both the methods were discussed by correlating the structure to the magnetism at nanoscales.

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.

Morphology and Mechanical Properties of NiZn Ferrite/Thermoplastic Natural Rubber Composite

In this paper the polymer nanocomposite of nickel zinc (NiZn) ferrite nanoparticles incorporated into the thermoplastic natural rubber nanocomposite (TPNR) were prepared via melt blending method. The effect of different NiZn loading (2-10 wt%) on morphology, tensile and dynamic mechanical properties of the obtained composites was investigated. It was found that NiZn ferrite is well dispersed in the thermoplastic natural rubber matrix. The tensile results indicated that filler loading has improved the tensile strength and Youngs modulus of the nanocomposite. However, the elongation at break decreased with increasing the percentage of NiZn. Dynamic mechanical test showed that the highest storage modulus is at 8 wt% filler. Any further increment of the filler content leads to the formation of agglomerate hence affecting the properties. The Scanning electron micrograph (SEM) micrographs reveal aspect ratio and filler orientation in the TPNR matrix also strongly promoted interfacial adhesion between the filler and the matrix to control its properties.

Magnetocrystalline anisotropy of NiZnFe2O4

A recently proposed model, based on the relative occupancy of tetrahedral and octahedral sites by different cations, was used to study the magnetocrystalline anisotropy of mixed Ni–Zn ferrite nanoparticles. According to this model, the total magnetocrystalline anisotropy is the weighted average of the contributions of the anisotropies of Fe3+ and M2+ ions in A and B sites. The model predictions are confirmed in the case of nickel–zinc ferrite.

Preparation, thermal, magnetic and microwave absorption properties of thermoplastic natural rubber matrix impregnated with NiZn ferrite nanoparticles

In this research, NiZn ferrite nanoparticles were incorporated in thermoplastic natural rubber matrix (TPNR) as reinforcing magnetic nanofiller by melt blending technique. TPNR was prepared from high-density polyethylene (HDPE), natural rubber (NR) and liquid natural rubber (LNR) in a ratio of 70:20:10 and later impregnated with 4, 8, 12 (wt%) of NiZn ferrite nanoparticles. Thermal stability, temperature dependence of coercivity and microwave absorption characteristics of the nanocomposite samples were investigated using thermogravimetric analyser (TGA), vibrating sample magnetometer (VSM) and vector network analyser (VNA), respectively. The results showed that the thermal stability of the nanocomposite samples has increased with increasing filler content in the TPNR matrix. Temperature dependence of coercivity for pure NiZn ferrite and nanocomposite samples exhibited immeasurable values below blocking temperature ( T B ), above which an abrupt increase was observed. In addition, the microwave absorption results showed multi-absorbing peaks characteristic with a great enhancement attained for 12 wt% nanocomposite at a sample thickness of 7 mm with a potential application in the X-band frequency.

Microstructural and magnetic behavior of mixed Ni–Zn–Co and Ni–Zn–Mn ferrites

Co/Mn substituted Ni–Zn ferrite nanoparticles were prepared by the sol–gel autocombustion method using metal nitrates in citric acid matrix to estimate the influence of substitutions on the microstructural and magnetic properties of the Ni–Zn ferrites. The synthesized powders were pressed into desired shapes and sintered at 1200°C for 4h in air atmosphere. X-ray diffraction analyses of the samples confirm single phase cubic spinel structures. Scanning electron micrographs of the materials reveal that the substitutions resulted in fine grained intragranular pore free microstructures. Initial permeability of the substituted ferrites exhibits stable frequency response up to 8–10MHz beyond which it exhibits a sharp resonance character while the relative loss factor has been found to be quite low up to this frequency. The results are explained in terms of the compositional, microstructural and anisotropic modifications brought about by the Co or Mn substitutions in these materials.