Nano Ferrites Research Articles

Al3+ and Cr3+ co-substituted NiZnCo nano ferrites: synthesis and structural properties

The Al3+ and Cr3+ substituted in Ni0.4Zn0.35Co0.25Fe2-x-yAlxCryO4 (x = y = 0.0, 0.05, 0.1, 0.15 and 0.2) ferrite nanoparticles were prepared with sol-gel method. X-ray diffraction (XRD), Field Effect Scanning Microscopy (FESEM), and Fourier Transform Inferred Spectroscopy (FT-IR) were used for their characterization. They have a single-phase spinel structure. The lattice constant decreases with increasing concentrations. Agglomerated small particles with stoichiometric proportions were obtained from FESEM. The region around 600 cm-1 and 400 cm-1 has two absorption bands related to two interstitial sites by FTIR agree with the spinel lattice.

Large electric field driven strain and enhanced multiferroic properties of Ce3+/BiFeO3Nano photo-catalyst

Photo-catalysis and electric field-driven strain in multiferroic nanomaterials have numerous applications in environmental remediation and actuators. In the present work, we investigated the effect of Ce3+/Ce4+ substitution on catalysis and strain-induced memory effect of Bi1-xCexFeO3 (x = 0.04, 0.08 and 0.12)nano ferrites, synthesized via sol-gel technique. The as synthesized nano ferrites were characterized via X-ray Diffractometer (XRD), field emission scanning electron microscope (FESEM), energy dispersive x-ray spectroscopy (EDS), BET surface area analyzer, UV–visible spectroscopy, Impedance analyzer, vibrating spin magnetometer (VSM), and P-E loop tracer for polarization behavior. The photocatalytic degradation capabilities of the photocatalysts were evaluated using the MB dye/Malathion pesticide under visible light, and degradation efficiencies were found to be increased from 48.38% to 72.07% due to band engineering and increased surface reactivity with the substitution of Ce3+/Ce4+ for MB dye and 64% for Malathion pesticide. With the maximum strain memory value (Sme %) 0.280, a considerable peak-to-peak strain (S+ and S−) and asymmetry factor (γs) were observed in the range 0.69–1.46%, 1.32–1.964%, and 18–31%, respectively. A significant enhancement in saturation polarization (Ps) values (0.84–1.22 μC/cm2) and saturation magnetization (Ms) values (0.89–2.57 emu/gm) were observed with the substitution of Ce3+/Ce4+ ions as evident from the ferroelectric P-E hysteresis loop and M − H hysteresis loop, respectively.

Ammonia gas sensing and magnetic permeability of enhanced surface area and high porosity lanthanum substituted Co–Zn nano ferrites

This work reports magnetic permeability and ammonia gas sensing characteristics of La3+ substituted Co–Zn nano ferrites possessing chemical formula Co0.7Zn0.3LaxFe2-2xO4 (x = 0–0.1) synthesized by a sol-gel route. Refinement of X-ray diffraction (XRD) patterns of the ferrite powders by the Rietveld technique has revealed the creation of single-phase spinel structure. The tenancy of constituent cations at tetrahedral/octahedral sites was obtained from the refinement of XRD. The crystallite sizes calculated from the W–H method vary from 20 to 24 nm. The scanning electron microscope (SEM) profiles of the ferrite samples were analyzed for the morphological details. The energy dispersive X-ray analysis (EDAX) patterns of the samples were obtained to test the elemental purity of the ferrites within their stoichiometry. The transmission electron microscope (TEM) image of the ferrite (x = 0.1) exhibits the spherical and oval shaped particles with a mean size of 20 nm. Fourier transform infra-red (FTIR) spectra were analyzed to confirm the superseding of La3+ cations at octahedral sites. The Brunauer-Emmett-Teller (BET) analysis of nitrogen adsorption-desorption isotherms of the ferrites was performed to investigate the porous structure and to determine the surface area of the nanocrystalline ferrites. The oxidation states of the constituent ions were confirmed by means of X-ray photoelectron spectroscopy (XPS). The complex permeability as a function of frequency was studied to explore the effects of structural parameters on the magnetic behaviour of the ferrites. Analysis of gas sensing properties of the ferrites have proved that the Co–Zn–La ferrite with controlled La composition can be utilized as an effective ammonia gas sensing material in commercial gas sensors.

Preparations and characterizations of Ca doped Ni–Mg–Mn nanocrystalline ferrites for switching field high-frequency applications

Ca-doped Ni–Mg–Mn spinel ferrites with compositions of Ni0·5Mg0·3Mn0.2CaxFe2-xO4 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared via sol-gel auto-ignition technique. TGA/DTA, FTIR, XRD, FESEM, and VSM were employed to evaluate the thermal, spectral, structural, morphological, and magnetic features of Ca-doped Ni–Mg–Mn spinel ferrites. TGA/DTA curves show the weight loss in the sample. This weight loss was attributed to the oxidation and decomposition of the sample contents at a temperature of 500 °C. XRD reveals a single-phase structure of the Ni–Mg–Mn nano ferrites. A single-phase orthorhombic structure was confirmed for Ca-doped Ni–Mg–Mn ferrites. Structural parameters such as lattice parameter, ‘da’, ‘db’, ‘dc’, and ‘dv’ were evaluated using unit cell software. The absorption peaks at 427 to 538 cm−1 confirmed the spinel structure, which was evaluated using FTIR. FESEM analyses showed that the agglomerations increased with the doping of Ca in Ni–Mg–Mn ferrites. Remanence, Y–K angles, saturation, coercive force, magnetic squareness, magnetic moment, and anisotropy constant were determined for Ca-doped Ni–Mg–Mn spinel ferrite samples. It is noticed that saturation increases from 29.157 to 51.322 emu/g, whereas remanence increased from 5.34 to 9.40 emu/g, respectively. The permeability, anisotropy constant, and magnetic moments were also found to increase with Ca doping. However, the Y–K angles increased with Ca concentration in Ni–Mg–Mn nano ferrites. In addition, the switching field distribution (SFD) and high-frequency response of all the Ca-doped Ni–Mg–Mn samples were also evaluated. Ca-doped Ni–Mg–Mn samples are suggested to be suitable for switching, filters, inductors, and microwave absorption applications because of the superparamagnetic nature of the prepared spinel ferrites.

Low-temperature large-scale hydrothermal synthesis of optically active PEG-200 capped single domain MnFe2O4 nanoparticles

Herein, we report an intrinsic fluorescence in polyethylene glycol (PEG) coated manganese ferrite (MnFe2O4) magnetic nano particles (MNPs). Generally, nano ferrites (NFs) do not show fluorescence characteristics, however, imparting fluorescence in these materials can be valuable for many applications as the stipulation of external control over the properties by external field provides an opportunity to develop active-controlled devices. In the present work, PEG-200 coated MnFe2O4 MNPs have been synthesized by a large-scale, facile one-pot hydrothermal method. The optical properties of MnFe2O4 MNPs have been by photoluminescence (PL) spectroscopy suggest that the prepared sample is showing sharp emission spectra at 422 nm, corresponding to the violet band, and second at 458 nm corresponding to the blue band. The presence of oxygen vacancy created at both tetrahedral and octahedral sites and shallow hole defects are responsible for the PL behavior in the PEG-coated MnFe2O4. The time-resolved PL (TRPL) results suggest that the MnFe2O4 MNPs have two decay times τ1=1.29ns and τ2=6.85ns which are non-correlated and correspond to different defect states. The electronic bandgap of the MNPs is 3 eV obtained from the Tauc plot using UV absorption spectra. Moreover, the structural analysis has been carried out using X-ray diffraction and various optical and magnetic properties have been correlated to structural parameters and cation distribution. The ferromagnetic resonance (FMR) spectra of the MnFe2O4 MNPs sample show a broad single peak which confirms the ferromagnetic characteristics of the sample and the g-value obtained for the sample is 1.98 which suggests that the super exchange interactions (SEI) dominates over the dipolar interaction. The M-H loop confirms the single domain nature of the sample and the saturation magnetization (SM) is 68 emu/g. The obtained value of SM is higher than the previously reported literature due to an increase in the occupancy of Fe3+ and Mn2+ ions at octahedral sites (Neel’s model). Further, the FTIR spectra confirm the spinel phase formation, and the size distribution and average size are obtained using electron microscopy analysis. The intrinsic fluorescent PEG-coated MnFe2O4 are highly suitable for a diverse range of biomedical (bio-imaging, sensing, magnetic resonance imaging (MRI) contrast agent), optoelectronics, and optical applications.

Impact of Adsorption of Rare-Earth Elements on the Structure and Magnetic Parameters of Mg- Nano Ferrite

Impact of Adsorption of Rare-Earth Elements on the Structure and Magnetic Parameters of Mg- Nano Ferrite

Investigation of structural and dielectric properties of Gd3+ substituted nickel-zinc ferrite prepared via low-temperature citrate gel self-ignited process

The productive of nanocrystalline Gd3+ substituted mixed Ni0.7Zn0.3GdxFe2-xO4 (where × = 0.000, 0.005, 0.010, 0.015, 0.020 and 0.025) spinel ferric material was synthesized using the low-temperature citrate assisted self-ignited process. The structure, microstructure, and elemental investigation were examined by XRD, SEM, EDX and TEM investigation. It revealed that the prepared accumulation a spinel system with an fd-3m space group. Scanning electron microscopy has shown the agglomeration of irregular morphology of nickel-zinc ferrite sample, EDX also confirms the presence of desired elements. TEM micrographs support the XRD data and the average particle size was estimated (approximately below 50 nm). The dielectric investigation is executed by using complex impedance spectroscopy in the frequencies 20 Hz to 2MH. Dielectric properties such as real (ε'), imaginary (ε'') parts in addition loss tangent (tan δ) decreased by means of rising frequency for prepared ferric materials. The investigation of complex impedance outcomes showed “the capacitive and reactive characteristics”. A study of the modulus electric evaluation suggested that relaxation processes in this nickel-zinc with Gd3+ substituted compositions are of a “non-Debye’s type”. Replacing Fe ions through Gd3+ ions significantly impacts synthesised nano ferrites' electrical properties.

Studies on structural and magnetic properties of cobalt substituted nickel nano ferrites prepared by microwave assisted self-propagating high temperature route

The Ni1-xCoxFe2O4(x = 0.2, 0.4 and 0.6) ferrite nanoparticles synthesized by novel Microwave assisted self-propagating route. The ferrite sample were studied using as ‘X-ray diffraction (XRD)’, ‘Fourier Transform Infrared Spectroscopy (FTIR)’, ‘Scanning Electron Microscope (SEM)’ and its magnetic properties. The XRD pattern reveals the single phase spinel structure confirmation Nickel ferrites with cobalt composition with crystallite size 30 nm. A decreasing pattern was observed in variation of porosity with Co content from 20.6 to 15.31%. The FTIR study describes, the sintering temperature affects the shift in tetrahedral site to lower frequency and preferences for site occupancy for Co and Fe ions. The SEM image shows average size of nano nanoparticles synthesized at 50 and 90O C about 50 and 60 nm. The increase in saturation magnetization from 29 to 37 emu/gm with increase in Co content due to its quick magnetic interaction. The said composition a may pplication of electronic memory devices, magnetic recording media.

Co-Existence of Experimental and Theoretical Studies of Ag Substituted Cobalt Nano Ferrites

Co-Existence of Experimental and Theoretical Studies of Ag Substituted Cobalt Nano Ferrites

Synthesis and characterization of zinc ferrite nanoparticles using prunus dulcis (almond gum) for antibacterial applications

ZnFe2O4 nanoparticles were synthesised by Sol-gel method, using zinc nitrate, ferric nitrate and almond gum (prunus dulcis). ZnFe2O4 nanoparticles were characterized by powder X-ray diffraction (XRD) and it indicates that cubic structure with average crystalline size of 9.81 nm. Crystalline size and microstrain were analysed to using W-H (Williamson- Hall) analysis. Lorentz factor (LF), Lorentz polarization factor (LPF), stress- strain plot (SSP), morphological index(MI) and dislocation density write calculated based on the X-ray diffraction data of ZF NPs. From FTIR analysis the peaks confirms the presence of Zn and Fe metals. The SEM analysis shows the agglomeration with spherical nature of ZF nanoparticles. The antibacterial activity study reveals the zone of inhibition of ZnFe2O4 nanoparticles which is used in pathogen gram positive bacteria and it shows the excellent antibacterial effect of ZF NPs. The VSM study shows the high saturation magnetization of prepared nanoparticles that were super-paramagnetism in nature and the zinc ferrite nano particles has soft magnetic properties. The magnetic saturation value of zinc ferrite NPs is found to be 0.1799 and the squareness ratio 0.2033.

Study of photo catalytical, antimicrobial activity, dielectric and ac impedance properties of Zn doped Mg nanoferrites synthesized from citrate gel auto combustion method

Mg–Zn nano ferrites with composition Mg(1-x)ZnxFe2O4 where x = 0.0 to 1.0 with 0.2 variation, were fabricated through citrate gel auto combustion method with step wise variation 0.2 mol%. UV–Visible spectroscopy confirmed the direct allowed transitions and optical band gap increased from 2.61ev to 2.71 with the addition of dopant Zn. The PL spectroscopy revealed that the broad near band edge emission in visible range 350–450 nm wavelength region. Antibacterial efficiency of the nano ferrites enhanced with the antibacterial dopant element Zn against gram positive Bacillus subtilis (MTCC 121) and gram negative Escherichia coli (MTCC 1687) strains. Organic dyes such as methylene blue and acid red were used to do photocatalytical degradation process and significant rate of degradation was found. Frequency dependent AC conductivity (σac) of the nano ferrites increased as a function of temperature and dopant Zn content. Dielectric parameters such as dielectric constant, dielectric loss (tan δ) were decreased with applied frequency. The results of dielectric studies reveals that the dielectric dispersion because of the hopping mechanism of electrons takes place in between Fe2+ and Fe3+ ions.

Investigation of structural and magnetic properties of La doped Co–Mn ferrite nanoparticles in the presence of α-Fe2O3 phase

Co0.5Mn0.5LaxFe2-xO4 nano ferrites with x = 0.0, 0.02, 0.04, 0.06, 0.08 and 1.0 have been synthesized by using sol-gel method. The crystalline structure of nano ferrites was examined using the X-ray diffraction and showed the presence of α-Fe2O3 phase along with the spinel phase in all compositions as hematite which it also confirmed from Mössbaur spectra. The crystallite size D and lattice strain have been estimated using the Williamson Hall plot. It is found that the crystallite size decreases with increasing of La content except at x = 0.08 while the strain has fluctuated in sign between plus and minus. Room temperature Mössbaur spectra have been recorded for all compositions. The value of isomer shift for both sites is found between 0.18 and 0.39 mm/s, indicating that Fe ions have a high spin state with Fe3+. It is also noticed that relative area (RA) of sextet B decreases with La3+ substitution, making the Fe3+ ions replaced by La3+ ions leads to decreasing of the average magnetization.

Correlation between the structural, magnetic, and dc resistivity properties of Co0.5M0.5-xCuxFe2O4 (M = Mg, and Zn) nano ferrites

Correlation between the structural, magnetic, and dc resistivity properties of Co0.5M0.5-xCuxFe2O4 (M = Mg, and Zn) nano ferrites

Magnetic Characterization of Co and Zn Nano Ferrites: Property Consideration for Oil-Spill Clean Up

Nano-magnetic particles are significantly finding applications in environmental remediation. This work studied the magnetic properties of Co and Zn nano-ferrites, CoFe2O4 and ZnFe2O4 respectively, with considerations for the properties that are desirable for oil spill cleanup. The ferrite nanoparticles were synthesized by the glycol-thermal method at 200 ºC for 6 hours using a stirred pressure reactor. Single phase spinel crystal structures were obtained for both samples as determined by an X-ray diffraction (XRD) machine. The high-resolution transmission electron microscope and surface electron microscope images showed nano structures. The magnetic properties and magnetic hyperfine parameters were determined using a lakeshore vibrating sample magnetometer and 57Fe Mössbauer spectroscopy. The XRD peaks were consistent with that of a single phase spinel structure. No impurity phase was detected. The nano-ferrites have crystallite sizes of about 10 nm and 17 nm for CoFe2O4 and ZnFe2O4. The nano almost-spherical nature of the samples was also confirmed from their morphology studies. The saturation magnetization of CoFe2O4 and ZnFe2O4 were about 50 emu/g and 30 emu/g respectively. They both exhibited superparamagnetic properties with a component of para-magnetism observed in ZnFe2O4 nano-ferrites. CoFe2O4 nano-ferrites exhibited better desired property for oil spill cleanup. The ZnFe2O4 nano-ferrites showed tendencies of slow response to magnetic field, however, it is more environmentally friendly. The magnetic hyperfine parameters and the isomer shift values for CoFe2O4 and ZnFe2O4 showed strong internal magnetic fields and the obtained values are consistent with spinel structure. The oxidation state of Fe was observed to be Fe3+. Due to the low coercivity and high magnetization values, these particles could be considered as potential candidates for oil spill cleanup. These desirable magnetic properties will improve the recyclability of the nanoparticles using low applied magnetic fields.

The Bioassay Guided Screening of Cryptolepis Extracts for Onward Synthesis of Nano Ferrites

In this study, various leaves and stem organic extracts were prepared using the solvents viz., n-hexane, ethyl acetate, ethanol and water, separately. Different phytochemical test for alkaloids, carbohydrates, oils, amino acids and others were performed to determine their presence in the extracts. These plant extracts were used for screening of sample via UV and HPLC techniques to compare the wavelength and absorbance, and retention time on chromatogram by extracts, respectively. The surface properties and size of nickel-zinc nano ferrites were evaluated by Energy-dispersive X-ray spectroscopy (EDX) and Scanning Electron Microscopy (SEM). The former, showed the presence of nickel (Ni) and zinc (Zn) weighing 4.27⁒ of N ,6.89⁒ of C and 35.5⁒ of O in the sample which confirmed the presence of nano ferrites in leaves and stem of C. buchanani.

Synthesis, Characterization, and NH3 Sensing Properties of (Zn0.7 Mn0.3-x Cex Fe2O4) Nano-Ferrite

This study includes the preparation of novel nano ferrite (Zn0.7 Mn0.3-x Cex Fe2O4) by using the auto combustion technique. For the following molar values, the percentage x was calculated: 0.0, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3. The nano-ferrite was calcined for 2 hours at 500°C. The energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD) and field emission scanning electron microscopy FE-SEM was used to examine structural, morphological, and sensing properties. The spinel cubic structure was revealed by XRD findings. The particle distribution was shown to contain voids by FE-SEM. The testing of sensing characteristics to NH3 gas indicated that the synthesized nano-ferrite has a small response time ranging from (15.3-25.2) s as well as a small recovery time between (36-58.5) s, also has a higher sensitivity of about 72.23%.

Investigation of Super‐Capacitive Properties of Nanocrystalline Copper‐Zinc (Cu0.5Zn0.5Fe2O4) Ferrite Nanoparticles

AbstractA comparative study is made between the structure and electrochemical properties of Copper‐Zinc (Cu0.5Zn0.5Fe2O4) ferrite nanoparticles prepared by chemical co‐precipitation. The obtained ferrites are characterized by FT‐IR, XRD, BET, and SEM techniques. The single‐phase cubic formation of Cu0.5Zn0.5Fe2O4 nano ferrites without any impurity peaks is confirmed by XRD analysis. FT‐IR spectrum exposes the occurrence of vibrating modes analogous to the cubic‐spinel ferrite structure of Cu0.5Zn0.5Fe2O4 nano ferrites. The magnetic hysteresis curve displays the superparamagnetic nature of the Cu0.5Zn0.5Fe2O4 nano ferrites. The electrochemical properties of obtained ferrites are studied using cyclic voltammetry, charge‐discharge, and electrochemical impedance spectroscopy. The as‐synthesized Cu0.5Zn0.5Fe2O4 sample acts as an excellent electrode material in a supercapacitor with a high specific capacitance energy density and a power density.

Preparation and Characterization of Nano Ferrites

Preparation and Characterization of Nano Ferrites

Synthesis, microstructure and magnetic properties of Co2+ and Al3+ substituted La-Zn nano ferrites

Co2+ and Al3+ substituted La-Zn ferrites synthesized by sol-gel auto-combustion method with glycine as a fuel, calcination temperature of samples confirmed from TGA analysis. The observed elemental analysis (EDAX) is in good agreement with the theoretical composition. The lattice constant decreases while the crystalline size increases with the increase in concentrations of dopant. Zn2+ ions prefer to occupy the tetrahedron site and other ions mainly enter octahedron site. The I.R. spectra have shown two principle absorption bands near 600 and 400 cm−1. SEM and TEM images reveal well defined nanoparticles with slight agglomeration. Magneton number decreased with dopant substitution.

Bioassay Guided Screening of Cryptolepis Extracts for Onward Synthesis of Nano Ferrites

A study was designed to investigate the presence of nanoferrites in Cryptolepis buchanani. In this study, various leaves and stem organic extracts were prepared separately using the solvents viz., n-hexane, ethyl acetate, ethanol and water. Different phytochemical tests for alkaloids, carbohydrates, oils, amino acids and others were performed to determine their presence in the extracts. These plant extracts were used for screening of sample via UV and HPLC techniques to compare the wavelength and absorbance, and retention time on chromatogram by extracts, respectively. The results showed the presence of alkaloids, carbohydrates and proteins in all the samples. However, other compounds were present randomly. Spectroscopy showed highest peaks with ethyl acetate extracts and the lowest with water. The surface properties and size of nickel-zinc nano ferrites were evaluated by Energy-dispersive X-ray spectroscopy (EDX) and Scanning Electron Microscopy (SEM). The former, showed the presence of nickel (Ni) and zinc (Zn) weighing 4.27⁒ of N ,6.89⁒ of C and 35.5⁒ of O in the sample which confirmed the presence of nano ferrites in leaves and stem of C. buchanani.