Fe2O4 Spinel Ferrite Research Articles

Electrical transport and dielectric relaxation mechanism in Zn0.5Cd0.5Fe2O4 spinel ferrite: A temperature- and frequency-dependent complex impedance study

In the present study, the frequency-dependent dielectric relaxation and electrical conduction mechanisms in sol-gel-derived Zn0.5Cd0.5Fe2O4 (ZCFO) spinel ferrite were studied in the temperature range of 343–438 K. The formation of the ZCFO spinel ferrite phase with space group Fd3m was confirmed by X-ray diffraction analysis. The dielectric relaxation and electrical conduction mechanisms were studied using complex impedance spectroscopy (CIS). In the Nyquist plots, depressed semicircles were fitted with an equivalent circuit model with configuration (RGBQGB) (RGQG), signifying the contributions from grain boundaries and grains to the charge transport mechanism in the sample. The frequency-dependent AC conductivity was found to follow Jonscher's power law, and the frequency exponent term depicted the overlapping large polaron hopping (OLPH) model as the dominant transport mechanism. The activation energies for conductivity, electric modulus and impedance were calculated to identify the nature of the charge carriers governing the relaxation and conduction mechanisms in the prepared sample. Complex modulus studies confirmed the non-Debye type of dielectric relaxation, whereas tangent loss and dielectric constant analyses confirmed the thermally activated hopping mechanism of charge carriers in Zn0.5Cd0.5Fe2O4 spinel ferrite.

Improving the Properties of Ni0.4Cu0.4Cd0.2Fe2O4 Spinel Ferrites via Heat Treatment for Electrical and Optoelectronic Applications

Improving the Properties of Ni0.4Cu0.4Cd0.2Fe2O4 Spinel Ferrites via Heat Treatment for Electrical and Optoelectronic Applications

Electronic, magnetic and optical properties of CoNi spinel ferrites doped by rare earth atoms: a density functional theory study

Density Functional Theory is employed to investigate how specific rare earth (RE) dopants (Pr, Y, Dy) affect the electronic, magnetic, and optical characteristics of Co0.5Ni0.5Fe2O4 (CN) spinel ferrites. The impact of RE atoms, which replace Fe ions in the supercell, is elucidated by analyzing the spin-resolved density of states, magnetic moment, and optical parameters. The findings demonstrate that both single and collective RE doping play a vital role in manipulating the key properties of these materials. Notably, we reveal that incorporating RE dopants into CN structures leads to a reduction in the energy band gap. Additionally, this work underscores substantial spin-dependent behavior and provides valuable insights into optical properties, suggesting that RE-doped CNs hold significant potential in the fields of spintronics and optoelectronics.

Investigating the adsorption of Malachite green and Methyl green onto synthesized Ni0.5Zn0.5Fe2O4 spinel ferrites

Nano-sized Ni0.5Zn0.5Fe2O4 spinel ferrites were synthesized at the nanoscale by the co-precipitation method via a sonochemical approach. High-intensity ultrasonic radiation treated the hydroxide suspension at 90 °C for 2 hours. Both the X-ray diffraction analysis (XRD) and the Fourier transform infrared spectra (FT-IR) analysis confirm the presence of the cubic spinel phase with a grain size of 15 – 25 nm. The vapor adsorption experiments confirmed that the pore surface area was found to be 95.34 m2/g by N2 adsorption desorption isotherm, and the material was mesoporous. The saturation magnetization of ferrite powders was investigated using a vibrating sample magnetometer (VSM). This work mainly focuses on the removal of Malachite green (MaG) and Methyl green (MG) with the help of adsorption technology from water using Ni0.5Zn0.5Fe2O4 spinel ferrites. The adsorption studies examined the impact of mass and pH, revealing that both factors influence adsorption. The optimum conditions for Malachite green and Methyl green adsorption onto the spinel Ni-Zn ferrites were 0.02 g for spinel mass, pH values (6−8). At 328 K, the maximum capacity for Ni0.5Zn0.5Fe2O4 spinel adsorbents was 82 and 180 mg/g MaG and MG, respectively. The removal efficiency for MaG and MG dye was respectively 95 % in 420 and 180 minutes. According to the kinetic studies, a pseudo-second-order model is the most suitable model for the adsorption process. The adsorption mechanism was examined by fitting the adsorption data to Langmuir, Freundlich, Radushkevich, and Temkin adsorption models. The Langmuir model can adequately describe results.

Electrical conduction mechanism and dielectric properties of the KSr0.5Fe2O4 spinel ferrite

Electrical conduction mechanism and dielectric properties of the KSr0.5Fe2O4 spinel ferrite

Single phase metamaterial behavior in [formula omitted] and [formula omitted] doped cobalt ferrites

This paper reports the characteristic properties of CoFe2O4(CFO), Co0.98Ag0.02Fe2O4(CAFO), and Co0.98Ti0.02Fe2O4(CTFO) spinel ferrites of Fd3‾m space group and grain size in the range of 160 – 170 nm. Fourier transform infrared spectra of these samples have revealed the metal-oxygen bands in the range of 448– 542 cm−1. Raman spectra have shown six distinct peaks corresponding to the mixed spinel structure, which have been used to calculate the cation distribution of the samples. The magnetic measurement at room temperature shows that after the doping of Ti4+ ions, the saturation magnetization increases from 47.70 to 66.68 emu/g, and coercivity decreases from 1.84 to 1.61 kOe, making the sample magnetically softer. The law of approach to saturation magnetization has been used to estimate the value of magneto crystalline anisotropy constant. The dielectric behavior of the samples has been thoroughly studied in this paper. The dielectric constant is positive below 300 °C; its value is comparable for CFO and CAFO samples but higher for CTFO. Above this temperature, the samples show an uncommon behavior of negative dielectric constant corresponding to the single phase metamaterial state and its value increases as temperature rises. This behavior can be interpreted with the help of Drude model of plasmonic resonance. The Nyquist plots change their properties from RC to RL type in this region. Such single phase metamaterials with negative dielectric constant could be useful for high temperature microwave applications.

Optical and magnetic studies of Co0.7Zn0.3Fe2O4 spinel ferrites with Dy3+ substituted for the application of sensors prepared through sol–gel process

Optical and magnetic studies of Co0.7Zn0.3Fe2O4 spinel ferrites with Dy3+ substituted for the application of sensors prepared through sol–gel process

The Influence of Calcination Temperature on Structural, Optical, and Impedance Spectroscopy Properties of Mixed Ni0.4Cd0.3Co0.3Fe2O4 Spinel Ferrites Synthesized Using the Sol–Gel Method

The Influence of Calcination Temperature on Structural, Optical, and Impedance Spectroscopy Properties of Mixed Ni0.4Cd0.3Co0.3Fe2O4 Spinel Ferrites Synthesized Using the Sol–Gel Method

PVC doped with Ni0.5Pb0.5Fe2O4 spinel ferrites nanoparticles: Fabrication, structural, optical, and radiation shielding properties

In this work, (Ni0.5Pb0.5Fe2O4) nano-ferrites has been prepared by a flash auto combustion technique, then new films of polyvinyl chloride (PVC) doped with x(Ni0.5Pb0.5Fe2O4) nanoparticles: x = 0 (PVC/PNF0) – 10 (PVC/PNF10) wt% have been fabricated. The nature, physical, linear optical as well as γ-ray attenuation capacity of the fabricated PVC/(Ni0.5Pb0.5Fe2O4) nanocomposites (NCs) sheets have been investigated. The crystalline state of (Ni0.5Pb0.5Fe2O4) NPs, and amorphous state of pure PVC, and PVC/(Ni0.5Pb0.5Fe2O4) films were performed by XRD measurements. The density (ρ) increased from 1.4451 to 2.613 g cm−3 for PVC/PNF0 and PVC/PNF10 sheets as the (Pb0.5Ni0.5Fe2O4) NPs content increased from 0 to 10 wt%. The direct band gap (Egapdirect) decreased from 5.259 to 2.969 eV, whereas Urbach energy (EU) increased from 0.439 to 4.812 eV. The index of refraction (n) for the fabricated films increased with increasing the concentration of (Ni0.5Pb0.5Fe2O4) NPs. The highest and lowest mass attenuation coefficient (MAC) values possessed at 0.015 and 15 MeV, respectively. The effective atomic number (Zeff) of the currently films followed the trend: (Zeff)PVC/PNF0 < (Zeff)PVC/PNF1 < (Zeff)PVC/PNF3 < (Zeff)PVC/PNF5 < (Zeff)PVC/PNF10. The half value layer (HVL) parameter possessed the trend: (HVL)PVC/PNF0 > (HVL)PVC/PNF1 > (HVL)PVC/PNF3 > (HVL)PVC/PNF5 > (HVL)PVC/PNF10. The fabricated PVC/(Ni0.5Pb0.5Fe2O4) NCs films can be used in electronic, optical, and radiation shielding applications.

Annealing Temperature Effects on Humidity Sensor Properties for Mg0.5W0.5Fe2O4 Spinel Ferrite.

The effects of annealing temperature on the structural, physical and humidity sensing properties of stoichiometric Mg0.5W0.5Fe2O4 spinel ferrite are investigated. In order to highlight the influence of sintering temperature on the structural, magnetic and electrical properties, ferrite samples were sintered for 2 h at 850 °C, 900 °C, 950 °C, 1000 °C and 1050 °C and the physical properties and humidity influence on magnesium-tungsten ferrite materials were analyzed. X-ray diffraction investigations confirmed the formation of magnesium-tungsten ferrite in the analyzed samples. SEM micrographs revealed the influence of annealing temperature on the microstructures of the samples and provided information related to their porosity and crystallite shape and size. This material, treated at different temperatures, is used as an active element in the construction of capacitive and resistive humidity sensors, whose characteristics were also investigated in order to determine the most suitable sintering temperature.

Investigation on magnetic critical behavior related to its magnetocaloric effect in Mn0.5Zn0.5Fe2O4 spinel ferrite

Investigation on magnetic critical behavior related to its magnetocaloric effect in Mn0.5Zn0.5Fe2O4 spinel ferrite

Structural and magnetic characterizations of NixCu0.8-x Zn0.2Fe2O4 spinel ferrites

The Ni-Cu-Zn ferrites are one of the most exciting spinel oxides so far because of its diverse applications. In the current study, the ratio of nickel and copper was varied keeping the concentration of zinc constant primarily aiming to examine its effect on cation distribution as well as structural and magnetic properties. The samples were synthesized via the conventional solid state sintering method at a temperature of 1050 °C then subjected to neutron diffraction studies. The magnetic properties were measured using a vibrating sample magnetometer (VSM) which complements the magnetic measurements from the neutron diffraction experiments. The ferromagnetic behaviors of these Ni-Cu-Zn ferrites were explained using the Y-K model and the canting of the magnetic moments were also measured. The lattice parameter ‘a’ was seen to reduce which results from the replacement of large Cu+ ions (0.73 with the smaller ionic radius of (0.69 ). To accommodate a large number of cations in the spinel lattice, the oxygen atoms restructure themselves as a result oxygen position parameter increased. The net magnetic moment per unit formula decreases as the Ni content is increased up to a level, after which the net moment increased.

A study of structural and dielectric properties of Zn2+ doped MnFe2O4 and NiFe2O4 spinel ferrites

In this report, we discuss the structural and dielectric properties of TM0.7Zn0.3Fe2O4 (TM = Ni, Mn) spinel ferrites. The ferrite materials under study were synthesized by the solid state reaction method. For structural elucidation, these materials were characterized by X-ray diffraction technique and Raman scattering Method. The analysis of XRD data obtained in the angular range of 10° – 80° revealed that both the samples under study have crystallized in cubic structure (Fd3m). The XRD results were verified by Raman spectral study from the display of fingerprint modes of vibration related to cubic structure acquired by these ferrite materials. The dielectric study infers the samples are extremely good dielectric materials with high dielectric constant and comparatively low loss value. The dielectric constant of Zn doped of MnFe2O4 is higher. However, the resonance like behaviour is observed for Zn doped NiFe2O4. The high dielectric constant and relatively low loss value infer their feasibility in advanced electronic device applications.

Effect of Cr3+ substitution on magnetic and electrical properties of (Ni0.3Cu0.7) Fe2O4 spinel ferrites

Chromium substituted copper base spinel ferrites (Ni0.3Cu0.7)CrxFe2-xO4 were prepared by Sol-gel method. Structural, magnetic and electrical properties were studied by utilizing X-ray diffractometer, Vibrating sample magnetometer, and precision LCR-meter using lab-tracer software. The X-ray diffraction analysis confirmed the formation of single phase fcc structure of the samples. The lattice constant and crystallite size decreased from 8.37-8.23Å and 53.09-35.36nm respectively with increasing content of Cr3+ ions. From MH loops it was observed that the saturation magnetization decreased and coercivity increased with increasing content of Cr3+ ions. Dc resistivity increased with increase of Cr3+ concentration and decreased with increase in temperature which shows the semiconducting behavior of ferrites. The dielectric constant, dielectric loss and tangent loss decreased with increase of Cr3+ concentration. The dielectric constant follows bilayer Maxwell Wagner model and Koop’s phenomenological theory while ac conductivity increased with increasing frequency following Jonscher’s power law.

SYNTHESIS, THERMAL, ELECTRICAL AND MAGNETIC PROPERTIES OF Bi0.6-xMn0.5Ni0.5Fe2O4 FERRITE

A series consisting of six samples of Bi0.6-xMn0.5Ni0.5Fe2O4 spinel ferrites with different molar concentrations have been fabricated by using the facile co-precipitation method. (x= 0.0, 0.10, 0.20, 0.30, 0.40 and 0.50). The synthesized series structural properties and phase information are studied using XRD. FESEM is used to explore the surface morphology and EDS is used to characterize the composition of elements in the nanoparticles. Raman Spectroscopy of the synthesized samples confirms the five Raman active bands Raman spectra i.e. A1g, Eg, and three belongs to T2g. These five peaks are at 200, 318, 477, 560, and 684 cm-1 indicates the successful confirms the formation of Bi0.6- xMn0.5Ni0.5Fe2O4 cubic nanoparticles. The vibrating sample shows a superparamagnetic character in magnetometry measurements. As the concentration of Bi is increased the saturation magnetization decreases from the value 82 emu/g. The graphs of TGA and DTA analysis showed weight losses with the rise in temperatures but no further weight loss was observed after 800°C and limits at 950°C. The dielectric measurements were performed between frequency ranges of 1MHz to 3GHz of the applied electric field. The dielectric parameters were observed to decrease by Bi substitutions whereas the particle size increases. This decreasing effect remains to continue by increasing the frequency. However, the resistance of the nanocomposite material is found to decrease. These dielectric parameters suggest that these nanocrystalline ferrites with the domino effect are suitable for microwave devices of GHz frequencies ranges.

Assessment of the critical behavior near the FM to PM phase transition in cubic Ni0.3−xCuxZn0.7Fe2O4 spinel ferrite

In this study, we report a thorough examination of the critical behavior of the cubic Ni0.3−xCux Zn0.7Fe2O4 (x = 0.0, 0.1 and 0.2) spinel ferrite which are crystallized with different irregular shapes of particle size (spherical,polygonal and cubic). The magnetic transition is ferromagnetic to paramagnetic state for all Cu-doped compounds. Different theoretical analyses, as the modified Arrott plot, Kouvel–Fisher method, and critical isotherm, have been used to identify the values of the ferromagnetic transition temperature TC, and the critical exponents of β, γ and δ. All the obtained values of critical parameters were found to be close to the 3D-Heisenberg theoretical model, which implies short-range magnetic interactions in Cu-doped compounds. The reliability of critical parameters was further checked through different methods, such as the Widom scaling relationship and the magnetic equation.

Co-Ni-Zn Ferrites Fabricated by Spark Plasma Sintering

Ni0,4Co0,2Zn0,4Fe2O4 spinel ferrites have been synthesized by precipitation method from an aqueous solution and bulk samples were fabricated by Spark Plasma Sintering (SPS) to investigate the microstructure and the mechanical properties. Although SPS is considered as a rapid compaction technique, its application is uncommon for ferrites due to reactions occurring between the graphite die and the ferrite powder at elevated temperature. In our tests this problem was circumvented by an alumina film applied on the die. We found that both chemical and phase composition could be retained in the sintered specimens after sintering. In addition, they exhibited improved mechanical properties in terms of hardness (10 GPa) and fracture toughness (2.7 MPa · m−1/2) as compared to conventionally sintered reference samples.

Modulation of Magnetic Properties in Ni0.4Zn0.6Fe₂O₄ Spinel Ferrite by Additives

Sintered NiSUB0.4/SUBZnSUB0.6/SUBFe₂O₄ ferrite with various additives, namely, CoO, Cu₂O, SiO₂, CaCO₃, and MgO was prepared by conventional ceramic processes. The formation of a single-phase cubic spinel structure was confirmed by powder X-ray diffraction. The microstructure and magnetic properties of the samples were significantly changed by the type of additive. In the frequency-dependent complex permeability (μ

Cd-doping effect on morphologic, structural, magnetic and electrical properties of Ni0.6-xCdxMg0.4Fe2O4 spinel ferrite (0 ≤ x ≤ 0.4)

The effect of Cd-doping on physical properties of Ni0.6-xCdxMg0.4Fe2O4 spinel ferrite has been investigated. Scanning electron spectroscopy (SEM) confirms the formation of grain and grain boundaries in these samples and the presence of all chemical elements introduced was confirmed by EDS. The X-ray analyses indicate that all the compounds have the cubic structure with Fd3¯m space group, cell parameter increase which Cd content. A ferromagnetic state at room temperature for all compounds is detected by a magnetization measurement of hysteresis loops. We note that the saturation magnetization increases with Cd content, however, the remnant magnetization, and the corrective field decreases. DC electrical conductivity analysis shows a semiconductor behavior for all sample. In addition, non-overlapping small polaron tunneling (NSPT) and the overlapping large polaron tunneling (OLPT) are the dominants conductions mechanisms in our samples.

Critical behavior in Ni0.15Cu0.15 Zn0.7Fe2O4 spinel ferrite

Abstract We report an in-depth investigation of the critical behavior in Ni0.15Cu0.15Zn0.7Fe2O4 (NCZFO) spinel ferrite synthesized via the solid-state reaction method. The structural analysis demonstrates that NCZFO belongs to the Fd 3 ¯ m space group of the cubic crystal system. The magnetic transformation in NCZFO at approximately TC = 290 K is of the second order, as per the Banerjee criteria. Employing various models, we have attempted to estimate the CP (critical parameter) values. The self-consistency of the CPs is confirmed by Widom's relation as well as the scaling hypothesis. The values of the CPs manifest that the magnetic ordering in NCZFO belongs to the Heisenberg theory in three dimensions, signifying short-range ferromagnetic interactions. The relationship between the exchange distance (J(r)) and the spatial distance (r) in NCZFO are expected to decline as J(r) ∼r−4.947.