Fe2O4 Nanoferrites Research Articles

Microwave-absorbing behavior of rare-earth-ion-doped copper manganese nanoferrites in X-band frequency

In this study, the technology important Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites were synthesized via sonochemical method and characterized to overcome the electromagnetic pollution problems. Crystalline, morphological, electrical, magnetic, and microwave-absorbing parameter were identified by doping of RE (La, Gd, Nd, and Dy) in Cu0.5Mn0.5Fe2O4 nanoferrites. The XRD analysis revealed a cubic spinel structure with a single-phase composition for Cu0.5Mn0.5Fe2O4 nanoferrites whereas Cu0.5Mn0.5Fe1.80RE0.2O4 (RE = La, Gd, Nd, and Dy) nanoferrites had a cubic structure with the presence of a secondary phase. SEM images confirmed the spherical shape of the particle and the grain size within the range of 19.25–28.19 nm, with elemental stoichiometry confirmed by EDS spectra. The dielectric constant and conductivity of Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were low at higher frequencies, which lead good candidates for microwave-absorbing technologies. The substitution of RE decreases saturation magnetization (43.38–23.96 emu/g) and squareness ratio values of prepared nanoferrites were less than 0.5. The SET values of the prepared nanoferrites were in the range of 32.31–41.81 dB. The minimal reflection loss (RL) values of Cu0.5Mn0.5Fe2O4 and Cu0.5Mn0.5Fe1.80RE0.2O4 nanoferrites were less than 10 dB and which indicated that the prepared nanoferrites possessed great potential for applications as microwave-absorbing materials.

Calcination temperature dependence of tri-magnetic nanoferrite Ni0.33Cu0.33Zn0.33Fe2O4: Structural, morphological, and magnetic properties

The calcination temperature plays a pivotal role in determining the physical and magnetic properties of ferrite nanoparticles, influencing their performance and applicability in various applications. In this study, Ni0.33Cu0.33Zn0.33Fe2O4 nano ferrites were produced using the coprecipitation method and subsequently calcined at different temperatures, specifically 500 °C, 550 °C, 600 °C, 650 °C, and 700 °C. The X-ray diffraction analysis confirmed the presence of cubic spinel ferrite phase (Fd-3m) and revealed an increase in crystallite size from 12.84 to 20.19 nm as the calcination temperature increased from 500 °C to 700 °C. X-ray photoelectron spectroscopy analysis provided insights into chemical oxidation states. Scanning electron microscopy and transmission electron microscopy images revealed that at higher calcination temperatures, nanoparticles tend to aggregate. This aggregation is associated with an observable rise in particle size, increasing from 18.16 to 29.11 nm for nanoparticles calcined at 500 °C and 700 °C, respectively. Energy-dispersive X-ray confirmed pure elemental compositions. Fourier transform infrared spectroscopy identified red and blue shifts in wavenumbers corresponding to tetrahedral and octahedral group complexes, respectively. Nanoparticles calcined at 700 °C exhibited the highest saturation magnetization (62.642 emu/g) and coercivity (75.27 G), as revealed from the vibrating sample magnetometry analysis. Upon increasing the calcination temperature from 500 °C to 700 °C, the ferromagnetic contribution was improved from 24.26% to 98.64% along with a reduction in superparamagnetic contribution from 75.74% to 1.34%, respectively. The electron paramagnetic resonance (EPR) study showed an increase in the values of g and ΔHpp with the rise in calcination temperature. This observation suggests an enhancement in dipole–dipole interactions. Furthermore, a linear relationship was discovered between the g factor and crystallite size, inducting the formation of single domain. Finally, altering the calcination temperature adjusted the physical and magnetic properties of Ni0.33Cu0.33Zn0.33Fe2O4 nanoparticles. This adjustment indicates their potential for versatile applications, particularly in hyperthermia treatment and as T2 contrast agents in magnetic resonance imaging.

Synthesis and characterization of PANI-CZF nanocomposites for enhanced electromagnetic interference shielding

The Zn0.5Cu0.5Fe2O4 nano ferrites were prepared by the solution combustion method using aloe vera gel. The polyaniline-Zn0.5Cu0.5Fe2O4 nano ferrite composites were prepared by Ex-situ polymerization method with different weight percentage ratio. The prepared samples were examined by X-Ray diffraction, SEM, EDAX, BET, TEM, VSM and Impedance analyser to investigate their structural, morphological, elemental analysis, average pore size and the porosity, magnetic, and dielectric properties, respectively. The cubic spinel structure was confirmed by X-ray diffraction patterns. Addition of PANI to zinc-copper nano ferrite exhibits shift in crystalline peaks towards larger angle. The existence of spherical and clumped particles was revealed by SEM examination. The retentivity and coercivity are determined and the magnetic moment values were decreases with increase in PANI to the ferrite nanocomposites. The ac conductivity constant at lower frequency and there is a sudden increase and decrease in its value as a function of frequency shows resonance behaviour. The CZF-1 (CZF 30%) composite shows highest ac conductivity and dielectric constant. The electromagnetic shielding interference studies were conducted for S-band frequency. The CZF-1 (CZF 30%) nano composite shows highest shielding effectiveness as compared to other composite in the frequency range 2 to 3 GHz. The experimental result showed that these materials are used for applications in electromagnetic interference shielding.

Structural investigation, magnetic and DC electrical resistivity properties of Co0.5-xNixZn0.5Fe2O4 nano ferrites

The Ni2+ substituted Cobalt-Zinc nano ferrites, designated as Co0.5-xNixZn0.5Fe2O4 with x values ranging from 0.0 to 0.5, were synthesized using the sol–gel auto-combustion method. Various characterization techniques, including x-ray diffraction (XRD), field-effect scanning electron microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM), and DC electrical resistivity measurements, were employed to analyze the prepared samples. XRD analysis revealed a cubic spinel structure with a lattice constant ranging from 8.384 to 8.412 Å. FESEM examination indicated non-uniform-shaped spherical grains in the nanometer range for the synthesized samples. The FTIR spectra of the spinel ferrites revealed two distinctive bands, ν2 (580–592 cm−1) and ν1 (390–412 cm−1), which are the characteristics of spinel-structured ferrite nanomaterials. With progressive substitution (x varying from 0.0 to 0.5), the saturation magnetization (Ms) values exhibited a gradual decrease, starting from Ms = 60.97 emu/g (at x = 0.0) and reaching Ms = 38.79 emu/g (at x = 0.5). A discernible pattern was observed in coercivity (Hc), which rose from Hc = 115 Oe (at x = 0.0) to Hc = 920 Oe (at x = 0.5), with peak values determined through VSM analysis. Similar to semiconductors, the electrical resistivity experienced a decline with increasing temperature, indicative of a negative temperature coefficient.

Structural and magnetic investigation on Cr3+ substituted Mn0.25Cu0.25Zn0.5Fe2O4 nano ferrites by co-precipitation route

A low-temperature co-precipitation approach was used to prepare Mn0.25Cu0.25Zn0.5Fe2-xCrxO4 (x=0.0, 0.4). The X-ray diffraction with most intense (311) peak and crystallite size in the range 25-29 nm confirms the formation of spinel nano ferrites. The transmittance within 400-600 cm-1 for all samples confirms Fe-O bond at tetrahedral and octahedral sites of prepared spinel nano ferrites demonstrated by FTIR. The soft magnetic nature of prepared material was recorded by VSM. The small Coercivity (16.6032 &20.9224 Oe), retentivity (1.4588 &1.5617 emu/g) and magnetic saturation (23.83 &31.8169 emu/g) demonstrates superparamagnetic, pseudo single domain and randomly oriented multi-domain nature of the nano ferrites. The produced superparamagnetic nano ferrites advantageous in high frequency and biomedical applications.

Retraction Note: Synthesis and investigation of Sm3+-doped Mn0.5Cu0.5Fe2O4 nanoferrites for microstrip patch antenna application

Retraction Note: Synthesis and investigation of Sm3+-doped Mn0.5Cu0.5Fe2O4 nanoferrites for microstrip patch antenna application

A new hybrid non-aqueous approach for the development of Co doped Ni-Zn ferrite nanoparticles for practical applications: Cation distribution, magnetic and antibacterial studies

Ni-Zn spinel nanoferrite with a composition Ni0.6-xZn0.4CoxFe2O4 (x = 0.00, 0.033, 0.066, 0.132, 0.264 and 0.528) was produced at a low reaction temperature using a novel hybrid direct non-aqueous approach that eliminates the need for a complexing agent and a precursor that adjusts pH. The developed Ni0.567Zn0.4Co0.033Fe2O4 (x = 0.033), Ni0.534Zn0.4Co0.066Fe2O4 (x = 0.066) and Ni0.072Zn0.4Co0.528Fe2O4 (x = 0.528) nanoferrites attains the single-phase spinel cubic nano symmetry with a crystallite size of 54.91, 47.55, and 48.98 nm, respectively. Spherical shaped nanoparticles with aggregated behaviour were confirmed for the produced nanoferrites. XPS spectra of Ni0.072Zn0.4Co0.528Fe2O4 nanoferrite confirms the detection of major photoemission peaks of Zn2p, Ni2p, Co2p, Fe2p, O1s, and C1s. According to the BET research investigation, Ni0.072Zn0.4Co0.528Fe2O4 nanoferrite having specific surface area of 2.309 m2/g. The highest saturation magnetization and coercivity of 37.09 emu/g and 108.85 Oe was attained at higher doping content of cobalt (x = 0.528). With this nano crystalline nature and excellent magnetic factors, the developed nanoferrites are highly beneficial for the recording media applications to get the suitable signal to noise ratio and also, for multi-layer chip inductors (MLCIs). From the antibacterial investigation, it was observed that the produced Co doped Ni-Zn ferrites (x = 0.033, 0.264) shows high zone of inhibition (ZOI) for E. coli and Bacillus subtilis but the rest of the samples (x = 0.0, 0.066, 0.132, 0.528) shows no ZOI for both the bacterial strains. Therefore, the prepared Co doped Ni-Zn nanoferrites also works as superior antibacterial agent for biological application.

La3+ substituted Ni0.5 Co0.5 Fe2 O4 nanoferrites: Magnetically separable catalysts for sunlight-driven photo-oxidative degradation of Methylene Blue

LaxNi0.5Co0.5Fe2−xO4 nanoparticles (x = 0.0, 0.03, 0.06, 0.09, 0.12) were investigated in the current work as Methylene Blue degradation catalysts. Using the citrate-aided sol-gel auto-combustion approach, the nanoferrites with homogenous size distribution were produced. Powder X-ray diffraction was used to analyse the structure of the material. The optical characteristics of ferrite nanoparticles were investigated using diffused UV–visible reflectance spectroscopy. It was noted that when the concentration of La3+ increased, the band gap of produced ferrites shrank. Morphological and compositional studies were performed by FE-SEM and EDX spectra. Surface area was depicted using BET analysis. Raman Spectroscopy was used to estimate the parameters of vibration. Testing has been done on synthesized nanoferrites to see whether they can remove Methylene Blue's concentration in water. In addition, it was examined how La3+ incorporation in Ni0.5Co0.5Fe2O4 nanocomposites resulted in aspects of doping ratio, reaction time and amount of catalyst. The most effective material, La0.06Ni0.5Co0.5Fe1.94O4, achieved a 98.69 per cent efficiency in 140 min. Due to three positive characteristics, including high recycling (up to five cycles), stability, and simplicity of separation using an external magnet, toxic dyes in actual wastewaters can be photodegraded in sunlight using La3+ substituted Ni0.5Co0.5Fe2O4 nanoferrites as an efficient and competitive catalyst.

RETRACTED ARTICLE: Synthesis and investigation of Sm3+-doped Mn0.5Cu0.5Fe2O4 nanoferrites for microstrip patch antenna application

RETRACTED ARTICLE: Synthesis and investigation of Sm3+-doped Mn0.5Cu0.5Fe2O4 nanoferrites for microstrip patch antenna application

Study of thermal, structural, microstructural, vibrational and elastic properties of MnxMg0.8–xZn0.2Fe2O4 (0.1 ≤ x≤ 0.7) ferrite nanoparticles

Sol-gel auto combustion method has been used to synthesize a series of MnxMg0.8–xZn0.2Fe2O4 (0≤ x ≤ 0.7 at a step of 0.1) nano ferrites. Thermogravimetric and Differential scanning calorimetry (TGA and DSC) studies revealed that the weight loss changes happened up to the temperature 700 °C. A stable ferrite phase without weight loss was found above 750 °C. XRD patterns gave the confirmation of cubic spinel phase of ferrite samples along with the minor amounts of α-Fe2O3 phase. The α-Fe2O3 phase appears to be increasing in the ferrite compositions for x ≥ 0.4. The experimental lattice parameter (a) and average crystallite size (<D>) are found to be in the range of 8.4205–8.4479 Å and 34.9–54.7 nm. A systematic variation was not found in both a and <D> with the substitution of Mn2+. FE-SEM micrographs do not provide individual particle sizes, but their nature showed the agglomeration of ferrite nanoparticles with magnetic interactions. The obtained higher and lower vibrational bands (υ1 and υ2) in FTIR spectra confirm spinel phase in support of XRD analysis. The ratio of bulk modulus to rigidity modulus (B/R) is greater than 1.75 for all ferrite compositions showing that the mechanical behaviour is ductile. The value of Poisson ratio (σ = 0.26) revealed the isotropic nature of ferrite compositions. Different parameters like cation distribution, substitution of Mn2+, configurational entropy, secondary phases and bond lengths are predominantly influencing the structural, vibrational and elastic properties of present ferrite compositions.

The role of nanoparticles inclusion in monitoring the physical properties of PVDF

In this work, the effects of CoxZn1-x Fe2O4 (x= 0, 0.5, 1) nanofillers on the PVDF polymer were scientifically studied. The structure and magnetic and optical properties were studied. XRD confirms the synthesis of nanofiller in a single phase. FTIR confirms the formation of nanoferrites. HRTEM shows that the prepared nanoferrites have a cubic-like shape. Also, the size and agglomeration increase with Co-Zn Fe2O4 nanoferrites compared to the other singles one. The effect of adding nanoferrites into PVDF matrix was studied using XRD, FTIR, FESEM, VSM, and UV-Vis. XRD and FTIR approved the complexation between PVDF polymer and nanoferrites. Also, addition of nanoferrites into PVDF leads to decrease the semi-crystalline nature of PVDF. FESEM showed that embedding nanoferrites into PVDF polymers creates pores and PVDF/Co-Zn Fe2O4 increases the pore size on the PVDF surface. The magnetic properties of PVDF were enhanced by adding the nanofiller. For example, saturation magnetization was increased from 269.31E−6 to 62.052E−3 by adding CoFe2O4 to PVDF polymer. Band gap calculation showed that PVDF/Co-Zn Fe2O4 has the lowest band gap energy which makes it useful in photochemical and electronic applications.

Exploring the influence of zinc substitution on structural, physical, magnetic, and DC resistivity properties of Co0.5Cu0.5Fe2O4 nano-ferrites

Exploring the influence of zinc substitution on structural, physical, magnetic, and DC resistivity properties of Co0.5Cu0.5Fe2O4 nano-ferrites

Dysprosium doped Cu0.8Cd0.2DyxFe2-xO4 nano ferrites: A combined impact of Dy3+ on enhanced physical, optical, magnetic, and DC-electrical properties

The current study focuses on the influence of rare-earth Dy3+ ion substitution on the structural, optical, electrical, and magnetic properties of Cu0.8Cd0.2Fe2O4 nano-ferrites. A series of Dy3+ doped Cu–Cd nano-ferrites with the chemical composition of Cu0.8Cd0.2DyxFe2-xO4 (x = 0.00, 0.025, 0.05, 0.075, and 0.10) were fabricated by CSGAC (citrate sol-gel auto combustion) technique using the corresponding elements in nitrate state and grounded powders were calcined at 650 °C for 4 h. These ferrite nanoparticles (NPs) structural, optical, magnetic, and electrical properties were investigated using P-XRD, FE-SEM, HR-TEM, FTIR, UV–Vis, ESR, VSM, and I–V measurements. The purity of the crystal structure, phase formation, and the various structural parameters of Cu–Cd-Dy nanoparticles have been analyzed from P-XRD data. The evaluated crystalline size ranges between 13.82 and 18.32 nm, and the lattice constant is between 8.349 and 8.385 Å. We observed the particles-size of 40–60 nm from HR-TEM and the grain size of 48–80 nm from FE-SEM images. The observed FTIR spectra demonstrated the spinel structure in the presence of the stretching bonds of metal-oxides and functional groups. The semiconducting character of the produced NPs is confirmed by the optical bandgap, which is in the range of 1.62 eV–1.73 eV. The g-value obtained from the electron spin resonance (ESR) spectroscopy is in the range of 2.613-2.333. The coercivity (Hc) reduced from 557.29-183.89 Oe at 300 K and 749.85-410.72 Oe at 15 K, respectively, with Dy3+ concentration. The maximum saturation magnetization obtained at 300 K temperature for x = 0.025 is 32.53 emu/g, whereas at 15 K for x = 0.1 is 38.85 emu/g. The results of the present examined samples with improved Hc, Ms, and Mr values at low temperature (15 K) than room temperature (300 K) revealed that Dy3+ doped Cu0.8Cd0.2Fe2O4 nanoparticles are helpful for high-density recording media application. By increasing the Dy3+ addition, the resistivity values were observed to increase from 9.107×106 to 1.166×108 Ω-cm.

Photocatalytic dye degradation efficiency and reusability of Cu-substituted Zn-Mg spinel nanoferrites for wastewater remediation

A series of unmodified and copper-modified zinc‑magnesium nanoferrites [Zn0.7Mg0.3-xCuxFe2O4 (x = 0.0, 0.02, 0.04, 0.06)] were prepared to degrade methylene blue (MB), a widely used textile dye and a threat to humans and the environment. The X-ray diffraction data reveals a spinel cube-like crystal structure with no additional phases. The sharpness and frequency of XRD peaks highlighted the nanocrystalline structure of fabricated photocatalysts. The calculated crystallite size (t) shows inconsistent behavior within 13–25 nm on doping copper ions within the crystal matrix of Zn-Mg nanoferrites. The morphological analysis showed the existence of spherical and aggregated nanoparticles for the synthesized Zn0.7Mg0.3Fe2O4 (x = 0.0), and Zn0.7Mg0.28Cu0.02Fe2O4 (x = 0.02) specimens. In the fabrication of Zn0.7Mg0.3Fe2O4 (ZMF1), Zn0.7Mg0.28Cu0.02Fe2O4 (ZMF2), Zn0.7Mg0.26Cu0.04Fe2O4 (ZMF3) and Zn0.7Mg0.24Cu0.06Fe2O4 (ZMF4) nanoferrites, the predicted band gaps were 2.30 eV, 2.18 eV, 2.07 eV, and 1.94 eV, respectively. The FTIR spectrum shows stretching vibrations in Fe-O complexes at the A-sites and B-sites, whereas the Raman spectrum exhibits five Raman active vibrational modes at 230–800 cm−1. The nanophotocatalysts showed excellent magnetization values around 4.44–12.92 emu/g with an applied field of 6000 Oe. In the photocatalytic degradation of methylene blue, Zn0.7Mg0.24Cu0.06Fe2O4 (x = 0.06) nanophotocatalyst showed a maximum rate constant of 0.0252 min−1 and 90% photocatalytic degradation efficiency. The nanoferrites showed excellent photocatalytic activity for five cycles and were easily separated using an external magnet.

Shielding performance of MnxNi0.8–xZn0.2Fe2O4 (0.1≤x≤0.7) for electromagnetic interference (EMI) in X-band frequency

A series of MnxNi0.8–xZn0.2Fe2O4 (0.1≤x≤0.7) nanoferrites were prepared by sol-gel auto combustion method. The TGA-DSC studies revealed the weight loss up to 700 °C and after no weight loss was found confirming the complete ferrite phase. Therefore, the as-burnt samples subjected to conventional sintering at 900 °C for 2h. The traces of XRD patterns revealed that formation of ferrite phase co-existed with secondary phases. The complex permittivity and permeability of present ferrite systems are found to be dependent of Mn2+ ion concentration. The real part of dielectric constant (ε′) for the all compositions are in the range of 5.184–6.951 at 8.2 GHz while it is 5.269–7.663 at 12.4 GHz. The values of ε′ at 8.2 GHz are slightly lower than the values at 12.4 GHz. The imaginary part of dielectric constant (ε″) was found to be in the range of 0.046–0.315 for all compositions over the entire range of X-band frequency (8.2–12.4 GHz). Compared to the variation of ε′, the variation of ε″ is more disorder. The number of semicircles in Cole-Cole plots is a witness of multiple di-electric relaxations of EM energy dissipation. The real part of magnetic permeability (μ′) is increasing, while imaginary part of magnetic permeability (μ″ ) is decreasing for all compositions as frequency is increasing from 8.2 to 12.4 GHz. Compared to the other ferrite compositions, the ferrite with low content of Mn2+ i.e. Mn0.1Ni0.7Zn0.2Fe2O4 ferrite system has higher value of μ″ and seems to be invariant over the entire X-band frequency range. The total effective shielding (SET) for all compositions is found to be in the range 37–12 dB. The highest values of SET 37 dB at 8.2 GHz and 28 dB at 12.4 GHz were reported for the ferrite composition Mn0.1Ni0.7Zn0.2Fe2O4. The shielding studies revealed that Mn–Ni–Zn ferrite systems are effectively suppressing electromagnetic interference (EMI) in X-band frequency. Comparatively, the ferrite system Mn0.1Ni0.7Zn0.2Fe2O4 is useful for the fabrication of EMI suppressor.

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.

Structural, Morphological, and Magnetic Properties of Nickel Substituted Cobalt Zinc Nanoferrites at Different Sintering Temperature

Co-precipitation was used for the preparation of Co0.5-xNixZn0.5Fe2O4 (x = 0 to 0.3) nanoferrites. The inverse spinel structure of the samples was clearly shown by the structural analysis of X-ray Diffractometer (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. We have studied the effect of sintering temperature (500oC) on the lattice constant and particle size using XRD. The average lattice parameters for the non-sintered and sintered samples were 8.377 Å and 8.354 Å respectively. For the non-sintered sample, the nickel concentration decreases the lattice parameter from 8.354 Å to 8.310 Å due to its smaller ionic radii than that of cobalt. While for a sintered sample at 500oC, the lattice parameter increases for concentration x=0.3 due to the thermal effect. The particle size calculated by Transmission Electron Microscope (TEM) agrees well with that of XRD. The morphological and compositional analysis was done with the help of Scanning Electron Microscopy (SEM) and the attached Energy Dispersive X-ray (EDX) Analyzer. The increasing percentage of nickel with decreasing percentage of cobalt shows that the cobalt is substituted by Nickel. The magnetic properties were studied by Vibrational Spectrometer (VSM). The value of saturation magnetization is higher for x=0.1 but lower for x=0.2 and 0.3 due to their particle size. The hysteresis loop of the samples their superparamagnetic behavior at room temperature.

Effect of Cu Substitution on Magnetic Properties of Co0.6Ni0.4Fe2O4 Nanoferrites

This work is focusing on synthesizing the cobalt nanoferrite materials substituted by copper forming Co0.6Ni0.4-xCuxFe2O4 with x = 0.0, 0.1, and 0.3 using the sol-gel auto-combustion method. The phase analysis of XRD showed the spinel structure with the lattice parameter in the range 8.36-8.39 Å. FESEM image showed the grain size initially decreasing and then increasing with Cu concentration. The FTIR curve's two absorption bands in the specified range of frequency assured the spinel nano ferrite structure. The values of remanent ratios obtained from VSM showed their isotropic nature forming single domain ferrimagnetic particles.

Utilization of the Ni0.1Co0.9Fe2O4 Nanocrystals for the Degradation of Crystal Violet

Ultrafine Ni0.1Co0.9Fe2O4 nanocrystals were synthesized by the simple co-precipitation route, and well-accurately characterized by X-ray diffraction (XRD), FT-IR spectra, and high resolution transmission electron microscopy (HTEM) technique. XRD investigation proved the evolution of the single-phase cubic spinel structure for these nanocrystals. The fine crystallite size R average value was 36.265 nm. FT-IR absorption spectra displayed the essential absorption bands that were related to their principle sites and main bonds. All the deduced parameters were affected by the presence of the Ni2+, Co2+, and Fe3+ cations in these nanocrystals. HTEM images showed accumulations for the nanoparticles, where the average particle size value was 42.9 nm and was slightly higher than the crystallite size R. Evaluation of photocatalytic activity for Ni0.1Co0.9Fe2O4 Nano-ferrites was obtained through the degradation of Crystal Violet (CV) dye (1 × 10-5 M) in aqueous solution under visible light irradiation using 100 Watt Tungsten lamp fixed at ~ 10 cm distance. As a result, usage of these new ultrafine Ni0.1Co0.9Fe2O4 nanocrystals gives a new marvellous route for the advancement of cost-effective technologies for quite good waste water recycling models, for raising water quality and for the promotion of fruitful efforts in improving treatment systems.

Thermal, microstructural and magnetic properties of manganese substitution cobalt ferrite prepared via co-precipitation method

Manganese-substituted cobalt nano-ferrites, Co(1−x)Mn(x)Fe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were synthesized using chemical co-precipitation method. Physical properties of Co(1−x)Mn(x)Fe2O4 nano-ferrites were then characterized using thermal gravimetric—differential thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrometer, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). TGA/DTA study indicates that the thermal stability of the prepared manganese doped cobalt ferrite nanoparticles. X-ray diffraction patterns of all the prepared ferrite samples show good in quality, pure nanosized, single-phased cubical spinel structures, with ferromagnetic behavior. We demonstrated that the expansion of lattice constant (a) and crystallite size (D) induced by manganese substituted of cobalt ferrites exerted remarkable effects on its structural and magnetic properties. The lattice constant (a) and crystallite size (D) increase with increasing manganese substituted cobalt ferrites. Williamson–Hall (W–H) method was used to evaluate the crystallite size and lattice strain of the Co(1−x) Mn(x)Fe2O4 nanoparticles samples by peak broadening. The calculated crystal size of Co(1−x) Mn(x)Fe2O4 nanoparticles on the W–H plots were highly intercorrelated with the HR-TEM and results of Scherrer Deby equation. The other physical parameters, such as X-ray density, hopping length, ionic radius, bond length, tetrahedral edge, octahedral edge, and unshared octahedral edge values were estimated from the highest intensity peak (311) of X-ray diffraction. The Fourier transform infrared (FT-IR) spectrometer of the Co–Mn ferrite nanoparticles systems were recorded in the frequency range of 200–1000 cm−1. FT-IR spectra show the two fundamental absorption bands of interstitial sub-lattice sites (M–O). The high absorption band (ν1) and the low absorption band (ν2) corresponds to the tetrahedral [A] and octahedral (B) sites, respectively, confirming the formation of single cubic spinel ferrite lattice system. The TEM results show that the ferrite nanoparticles have a nearly spherical shape with some agglomerations. From the analysis of VSM, the values of saturation magnetization (Ms) increases from 31.46 to 37.16 emu/g, then decreases with increasing Mn2+ ions substitution in the Co-ferrite system. The coercivity of the Mn2+ ions substituted cobalt ferrites increases up to x = 0.6 followed by a decrease. The optimized magnetic parameters suggest that the material with composition Co0.6Mn0.4Fe2O4 may be suitable for longitudinal magnetic recording media and other various technological applications.