Nickel Nanoferrites Research Articles

Chromium substitution effect on the structural, optical, electrical and magnetic properties of Nickel ferrite nano particles; synthesized by an environmentally benign auto combustion method

An environmentally benign auto combustion method was employed to synthesize chromium substituted nickel ferrite nano particles from aqueous metal nitrate solutions. XRD analysis indicates reduced phase impurity of nickel ferrite sample with increasing Cr substitution for Fe. The same may be observed along with cation redistribution in Raman analysis of the samples. All the above samples show double optical band gap in the visible region of the electromagnetic spectrum. The resistivity values of all the above samples indicate an enhancement with increase in chromium substitution. Particles show magnetic core shell model and saturation magnetization increased with increasing Cr substitution.

Preparation and characterization of nickel ferrite nano particles by co-precipitation method with citrate as chelating agent

In this era, the latest trend in materials science and related fields is fabrication, characterization and applications of nano materials. In the present study, NiFe2O4 nano particles were synthesized by co-precipitation method with citrate as chelating agent. The synthesized materials were calcinated at different temperatures 400, 600 and 800 °C and characterized by using XRD. The NiFe2O4 nano particles calcinated at 600 °C were characterized by using FE-SEM with EDAX, FE-TEM with SAED pattern, DLS Zeta Potential and CV. The formation of single phase nanosized nickel ferrite was investigated by XRD and the particle size linearly increased with the temperatures was noticed. The surface morphology of NiFe2O4 studied by FE-SEM was cubic spinel structure and it was confirmed by FE-TEM. The element identified in the NiFe2O4 nanoparticles from EDAX analysis were Fe, Ni and O. Stability of the particle was analysed through Zeta potential study. Capacitance value 123 Fg−1 was observed from CV study and it was suitable for super capacitance application.

Synthesis of 5‐substituted 1H‐tetrazoles using a recyclable heterogeneous nanonickel ferrite catalyst

An efficient method was developed for the [2 + 3] cycloaddition of sodium azide with nitriles to afford 5‐substituted 1H‐tetrazoles using nanonickel ferrite (NiFe2O4) as an effective heterogeneous catalyst in dimethylformamide. The main advantages of this method are high yields, simple methodology and easy work‐up. The catalyst can be recovered and reused for several cycles with predictable activity. Copyright © 2015 John Wiley & Sons, Ltd.

Role of copper on structural, magnetic and dielectric properties of nickel ferrite nano particles

Copper doped nickel ferrites Ni(1−x)CuxFe2O4 (where x=0.2, 0.4, 0.6) nanoparticles are prepared by co-precipitation method and sintered at 600°C. The XRD study confirms the formation of single-phase cubic spinel Ni–Cu ferrites. The particle size increases with Cu substitution. FT-IR spectra confirm the absorption bands around 554–547cm−1 for the tetrahedral sites and around 448–450cm−1 for the octahedral sites. The inclusion of copper shifts the tetrahedral band to lower values. The saturation magnetization (Ms) and remanent magnetization (Mr) decrease with increase in copper concentration and the coercivity (Hc) is found to increase for all the compositions sintered at 600°C. The dielectric constant decreases drastically for all the compositions and reaches a constant value. These nanoparticles can be tested for humidity sensing applications.

Nano nickel ferrite (NiFe2O4) as anti-corrosion pigment for API 5L X-80 steel: An electrochemical study in acidic and saline media

There have been increased interests in using nanoparticle-based anticorrosion pigments in various industrial applications such as working fluids, lubricants, oil and gas fields, cooling water, anticorrosion coatings etc. In this article, nano-nickel ferrite used as corrosion inhibitor pigment for carbon steel in 1 M sulphuric acid and 3.5% NaCl solutions. The pigment has been characterized using Transmission electron microscopy and X-ray diffraction. Effects of solutions having varying concentrations of the pigment on corrosion response are studied using electrochemical cell via open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic methods. Results indicate that the corrosion inhibition is inversely proportional to increasing cations concentrations. Increased corrosion with increasing cations concentration has been attributed to the domination of galvanic corrosion of the steel which occurs via adsorption of metallic cations produced from nickel ferrite such as Ni++ and Fe++. Marked inhibition efficiency can be of significant importance for industries.

Structural and Electric Investigations of Al-doped nano Nickel Ferrite

Structural and Electric Investigations of Al-doped nano Nickel Ferrite

ChemInform Abstract: Highly Active Recyclable Heterogeneous Nanonickel Ferrite Catalyst for Cyanation of Aryl and Heteroaryl Halides.

Magnetic nickel ferrite nanoparticles are found to be an efficient catalytic system for cyanation reactions of various types of aryl halides under conventional heating conditions. All the reactions result in very good to excellent yields under optimized reaction conditions. Furthermore, the catalyst is easily removed from the reaction medium and can be reused further in several subsequent runs. Copyright © 2014 John Wiley & Sons, Ltd.

Microstructure evolution, dielectric relaxation and scaling behavior of Dy-for-Fe substituted Ni-nanoferrites

Dy-substituted nickel nanoferrites have been investigated in order to explore the possibility of Dy-for-Fe substitution in nickel ferrites, as well as the effect of the substitution on the microstructural and electrical properties. The samples were prepared by a simple citrate nitrate auto-ignition method. Rietveld analysis of the X-ray diffraction profiles confirmed the Dy-for-Fe substitution in this spinel ferrite. A slight increase in lattice parameter and microstrain due to incorporation of Dy is observed. The transmission electron microscopy also confirmed the high crystallinity of the prepared samples. It has been found that the doped samples show ionic conductivity 1 to 2 orders greater than that of the undoped sample at a particular temperature. In addition, the doped sample shows lower dielectric loss than the undoped sample. The frequency dependence of the dielectric permittivity has been analyzed using the Havriliak–Negami formalism. The time-temperature superposition principle has been established by the scaling of different spectra.

Plasma Synthesis of Facetted Nickel nano-Ferrites with Controlled Stoichiometry

Plasma Synthesis of Facetted Nickel nano-Ferrites with Controlled Stoichiometry

Comparison of different methodologies for obtaining nickel nanoferrites

Nickel nanoferrites were obtained by means of four different synthetic wet-routes: co-precipitation (CP), sonochemistry (SC), sonoelectrochemistry (SE) and electrochemistry (E). The influence of the synthesis method on the structural and magnetic properties of nickel ferrite nanoparticles is studied. Although similar experimental conditions such as temperature, pH and time of synthesis were used, a strong dependence of composition and microstructure on the synthesis procedure is found, as electron microscopy, X-ray diffraction and Mössbauer spectroscopy studies reveal. Whereas by means of the CP and SC methods particles of a small size around 5–10nm, respectively, and composed by different phases are obtained, the electrochemical routes (E and SE) allow obtaining monodisperse nanoparticles, with sizes ranging from 30 to 40nm, and very close to stoichiometry. Magnetic characterization evidences a superparamagnetic behavior for samples obtained by CP and SC methods, whereas the electrochemical route leads to ferromagnetic ferrite nanoparticles.

Structural Properties and Electrical Conductivity of Copper Substituted Nickel Nano Ferrites

A series of copper substituted nickel nano ferrites with the compositional formula Ni1-XCuXFe2O4 (X=0, 0.2, 0.4, 0.5, 0.6, 0.8 and 1.0) were prepared by the Citrate gel auto combustion technique and sintered at 700 o C for 5 hr. The X-ray difractrograms (XRD) clearly exhibited the existence of single phase cubic spinel structure. The crystallite size was found in the range of 36-58nm. With the increment of Cu content the X-ray density and porosity were found to increase where as the bulk density was found to decrease. The DC electrical properties were carried out by two-probe method from room temperature to well beyond the Curie temperature. DC electrical resistivity decreases with increase of temperature ensuring the semiconducting nature of the ferrites. The DC electrical conductivity found to increase with increase of Cu content and reaches maximum at X=1.0 at which the activation energy for conduction becomes minimum. The activation energy in the ferrimagnetic region is in general lesser than that in the paramagnetic region. The activation energy was found to decrease with the increase of Cu content. The Curie temperature determined from DC electrical properties was found in satisfactory agreement with that determined from Loria technique. The DC electrical resistivity results are discussed in terms of hopping model. 1-xCux Fe2O4 (X= 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0) were

Improved initial discharge capacity of nanostructured Ni-Co spinel ferrite as anode material in lithium ion batteries

Nanostructured nickel ferrite doped with cobalt is synthesized by co-precipitation method. The sample is characterized using X-ray diffraction, Fourier Transform Infra Red and Transmission Electron Microscope. Specific surface area and porosity analysis are performed through Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption isotherms. The magnetic properties are also studied. Spinel cubic structure with nanoparticles and porous surface is confirmed. The electrochemical properties of the nanostructured spinel are investigated including the cycling performance as anode material for lithium ion batteries. The results show that the sample has a high discharge capacity, especially the first five cycles, at current density of 2.43 mA/cm2 compared to recent performances reported at low current density (0.2 mA/cm2) for pure and composite of nanonickel ferrite. All results and data are correlated and discussed.

Hydrothermal Synthesis, Structural and Electrical Properties of Antimony (Sb3+) Substituted Nickel Ferrites

Antimony (Sb3+) doped nickel ferrites have been synthesized by hydrothermal route using an autoclave at 160 ∘C for 12 hours. Pure spinel phase NiSb x Fe2−x O4 (x=0.0 to 0.1) with step increment of 0.035 has been prepared by sintering the precursor samples at 500 ∘C. Structural studies have been performed using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Lattice parameter and X-ray density found to increase with increase in the antimony concentration. Average crystallite size lies in the range of 14 to 24 nm ± 2 nm. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) have been used to characterize the morphology and sizes of nanoparticles. Electrical properties were analyzed by measuring DC-electrical resistivity, complex dielectric permittivity, AC conductivity and complex electrical modulus analysis. DC resistivity of nickel ferrites decreases due to the substitution of antimony from 6.7×108 to 3.4×107 Ω-cm. Dielectric permittivity and losses were studied in the frequency range of 20 Hz–5 MHz and found to increase due to addition of Sb3+ in nickel nanoferrites at room temperature. High dielectric permittivity and conductivity made this material a compatible option for single-layered and multilayered chip inductors.

Dielectric Behavior and A. C. Conductivity Studies on Nickel Nanoferrites Synthesized by Solution Combustion Method

Nanoscale Nickel ferrite particles were prepared by combustion method using nickel nitrate as oxidizer and urea as a fuel. The structure of the sample is studied with X-ray diffraction (XRD) using Cu-Kα radiation. The X-ray diffraction analysis revealed the nanocrystalline nature in the prepared ferrite samples. Dielectric studies have been undertaken over a wide range of frequencies (100Hz-5MHz) for Nickel nanoferrites at room temperature. Dielectric properties such as dielectric loss tangent (D), dielectric constant (ε′ ) and dielectric loss factor (ε″) are found to decrease with the increase in the frequency. Observed variations are understood on the basis of Koop’s phenomenological model. Further, a. c. conductivity of the Nickel nanoferrite was found to increase with the increase in the frequency. Observed variation in the a. c. conductivity with the frequency has been understood on the basis of electron hopping model.

Magnetodielectric composite with NiFe2O4 inclusions as substrates for microstrip antennas

Magnetodielectric composite relevance as substrate for microstrip antenna is studied. Synthesized nano nickel ferrite (NiFe2O4) of crystallite size ~12 nm dispersed in low density polyethylene (LDPE) is developed for the said purpose with varying filler concentration (volume %) from 1% to 5% (0.01 to 0.05). Morphological characterization of the composite is carried out using scanning electron microscopy. Permittivity and permeability of the composites in X-band frequency range is determined using in-touch non-destructive technique and cavity perturbation technique, respectively. The complex permittivity of the substrates varies from ~6.091 - 8.427 and complex permeability, ~1.0345 - 1.1998 for different filler concentrations s. 4πMs value and coercivity is measured using vibrating sample magnetometry. Verification of these composites as potential substrates for microstrip patch antenna is carried out by fabricating simple rectangular patch at 10 GHz using transmission line model. Rectangular patch is designed on 0.01, 0.03 and 0.05 filler concentration composite system. The return loss for the 0.01 vol.% composite system is found to be ~-17 dB. E and H plane radiation pattern shows high directivity and negligible side lobe level.

Synthesis and Characterization of Copper Substituted Nickel Nano-Ferrites by Citrate-Gel Technique

Mixed Copper substituted Nickel nano-ferrites having the chemical formula Ni1-xCuxFe2O4 (where x = 0, 0.2, 0.4, 0.6, 0.8, 0.9 and 1.0) were synthesized by citrate gel technique. The crystal structure characterization and morphology were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). An elemental composition of the samples were studied by energy dispersive X-ray Spectroscopy (EDS). Lattice parameter, X-ray density, Volume of the Unit Cell and The values of the hopping length for octahedral (dB) and tetrahedral (dA) sites were calculated. The observed results can be explained on the basis of composition.

Role of Co–Cr substitution on the structural, electrical and magnetic properties of nickel nano-ferrites synthesized by the chemical co-precipitation method

Nano-spinel nickel ferrites doped with Co–Cr at iron and nickel sites are synthesized by the chemical co-precipitation method and are characterized by the XRD, DC electrical resistivity and hysteresis loops measurements. The XRD analyses confirm the formation of single spinel phase and the crystallite size calculated by Scherer's formula is found in the range of 17–19nm. This crystallite size is small enough to obtain the suitable signal to noise ratio in the high density recording media. The values of electrical resistivity (8.28×107 to 29.6×107ohmcm), activation energy (0.545–0.884eV), saturation magnetization (23.67–33.49emug−1) and remanence (12.48–18.67emug−1) are increased up to a doping level of x=0.2 and then starts to decrease. The increase in electrical resistivity, saturation magnetization and remanence suggest that the material with composition Co0.2Ni0.8Fe1.8O4 can be used for applications in microwave devices and high density recording media.

Structural, dielectric and electrical properties of zinc doped nickel nanoferrites prepared by simplified sol–gel method

Zinc doped nickel ferrite nanoparticles having the general formula Ni1−xZnxFe2O4 (x = 0.1, 0.2, 0.3, 0.4, 0.5) were prepared with simplified sol–gel method. The structural and dielectric properties of these samples sintered at 750 ± 5 °C were studied. X-ray diffraction patterns confirm the single phase spinel structure for prepared samples. The scanning electron microscope images indicated that the particle size of the samples lies in the nanometer regime. The dielectric constant (er) and dielectric loss tangent (tan δ) of nanocrystalline nickel ferrites were investigated as a function of frequency and Zn concentration. The dependence of er and tan δ on the frequency of the alternating applied electric field is in accordance with the Maxwell–Wagner model. The prepared samples have a lowest dielectric constant compared to the already reported samples of the same composition to the best of our knowledge. The effect of Zn doping on the dielectric properties of nickel ferrites is explained on the basis of cations distribution in the crystal structure.

Cure characteristics and mechanical properties of rubber ferrite composites based on nano-nickel ferrites

Ultra fine nickel ferrite have been synthesized by the sol-gel method. By heat treating different portions of the prepared powder separately at different temperatures, nano-sized particles of nickel ferrite with varying particle sizes were obtained. These powders were characterised by the X-ray diffraction and then incorporated in the nitrile rubber matrix according to a specific recipe for various loadings. The cure characteristics and the mechanical properties of these rubber ferrite composites (RFCs) were evaluated. The effect of loading and the grain size of the filler on the cure characteristics and tensile properties were also evaluated. It is found that the grain size and porosity of the filler plays a vital role in determining the mechanical properties of the RFCs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Síntese, por reação de combustão em forno de microondas, de nanoferritas de níquel dopadas com cromo

Pós nanométricos de ferritas de níquel dopadas com cromo foram sintetizados por reação de combustão em forno de microondas. A influência da concentração de Cr3+ nas proporções de x = 0; 0,5 e 1 no sistema NiCr xFe2-xO4 foi investigada. Os pós foram preparados de acordo com o conceito da química dos propelentes e aquecidos em forno microondas com potência 980 W. Os pós sintetizados foram caracterizados por difratometria de raios X, adsorção de nitrogênio (método BET), microscopia eletrônica de varredura, picnometria de hélio e medidas magnéticas. Os resultados mostraram que foi possível obter nanopós de ferritas de níquel dopadas com cromo e que a elevação da concentração de cromo causou um aumento no tamanho de partículas (15 nm para 55 nm) e redução nos parâmetros magnéticos.