Single Spinel Structure Research Articles

Rietveld refined crystal structure, magnetic, dielectric, and electric properties of Zn substituted Ni-Mg ferrites

Sol − gel technique was used to synthesize Ni0.7-xZnxMg0.3Fe2O4 (Ni – Zn – Mg) ferrites with x = 0.1, 0.2, 0.3, 0.4, 0.5. Formation of single phase cubic spinel structure of the synthesized samples was confirmed by employing Rietveld refinement technique. Spherical and inhomogeneous distribution of grains was observed from Transmission Electron Microscopy (TEM) image. The frequency dependent initial permeability (μi), real part of initial permeability (μ′), imaginary part of initial permeability (μ″) was studied for synthesized samples. For zinc content x = 0.2 in Ni – Zn – Mg ferrites μi is observed to be high as compare to other compositions and that attributed to grain size. DC electrical resistivity (ρdc) analysis shows both conducting and semiconducting behavior for all the samples. Room temperature electrical resistivity values were observed to be lower for lower content of zinc and higher for higher content of zinc and that attributed to the hopping mechanisms at octahedral site. The decreasing trend of Curie temperature was observed with increase in zinc content in Ni – Zn – Mg ferrites. Frequency dispersive dielectric properties study of Ni – Zn – Mg ferrites revealed normal dielectric behavior.

Influence of Nd3+ on structural, electrical and magnetic properties of Ni-Cd nanoferrites

Here in we report the nanocrystalline Ni1-xCdxNdyFe2-yO4 (0 ≤ x ≤ 1.0 in steps of 0.2: y = 0.0; 0.1) ferrites were synthesized by novel solution combustion technique. The sintered powders have been characterized by X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive analysis by x-rays (EDAX) methods. DC electrical conductivity carried out by two probe method. Magnetic parameters were measured using vibrating sample magnetometer with an applied magnetic field up to 15 kOe at 300K. The XRD results confirmed the formation of single phase cubic spinel structure formation. It was found that the lattice parameter increased with increase in Cd2+ ion. The crystallite sizes have been found in the range of 44.24 nm–15.467 nm. Moreover, the formation of two prominent absorption bands confirmed the spinel structure. The SEM micrographs evidenced almost spherical shaped, agglomerated and grainy structure of nanoferrites. Moreover, the Curie temperature (TC) was decreased with increasing temperature and exhibit the semiconducting behaviour. Further, saturation magnetization (MS), remanence magnetization (Mr); coercivity (HC) were decrease with increase in the magnetic field. The magnetic parameters; MS, Mr, nB increases attain maximum thereafter decreases with increase in Cd2+ ion and Nd3+ ion content.

Physical properties of La3+ ion doped Ni[sbnd]Zn based spinel ferrite nanomaterials for technological applications

Spinel ferrite nanoparticles are extensively utilized in various everyday applications due to their exceptional capabilities. They are highly effective and efficient for various applications such as energy storage devices, microwave, electrode design, fuel cells, and recording media. Based on these applications, five samples of lanthanum doped nickel‑zinc spinel ferrite Ni0.5Zn0.5LaxFe2-xO4 nanoparticles were synthesized using the sol-gel auto-combustion technique. The lanthanum concentrations varied as x = 0.00, 0.05, 0.10, 0.15 and 0.20. X-ray diffraction (XRD) analysis revealed the formation of single phase cubic spinel structure of the prepared samples. The crystallite size was determined using the Scherrer formula and the values lies in the range of 9.22 to 20.09 nm. The chemical composition of the prepared samples was confirmed using Fourier transform infrared spectroscopy (FTIR) analysis. Transmission electron microscopy (TEM) confirmed the agglomeration and spherical shape morphology of the nanoparticles with an average particle size of 40 nm. Magnetic properties along with La3+ ion concentrations were investigated using the vibrating sample magnetometer (VSM). The dielectric properties of the prepared samples were carried out using impedance analyzer with an applied frequency ranging from 1 MHz to 3 GHz. Furthermore, the polarization mechanism in the applied frequency range was discussed with relaxation behavior at high frequency. The impact of La3+ concentrations on different parameters such as dielectric constant, impedance, electric modulus, tangent loss, and Ac conductivity were also investigated. The investigation of dielectric parameters. The relaxation mechanism at high frequency provided a significant impact of such type of materials to store energy due lake of hopping between the tetra and octahedral sites by addition of La3+ doping. The prepared samples exhibit excellent magnetic as well dielectric properties which makes suitable for microwave devices and soft magnetic applications.

Elucidation of structural, electromagnetic, and optical properties of Cu–Mg ferrite nanoparticles

Copper doped magnesium ferrite, Mg1-xCuxFe2O4(x = 0.0–1.0) nanomaterials were synthesized via. sol-gel method sintered at 600 °C for 2 h. The synthesized materials were characterized using modern sophisticated techniques viz. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy, Energy dispersive x-ray spectroscopy (EDS), Vibrating sample magnetometer, UV–visible diffuse reflectance spectra and Impedance analyzer. XRD analysis revealed that all the samples were single phase cubic spinel structure with Fd3m space group and investigated the change in structural parameters with copper concentration. The average crystallite size in the range of 11–23 nm and lattice parameters decrease with increasing Cu doping, due to the cationic distribution and ionic radius. The SEM images show the agglomeration of the particles with spherical like shape and elemental percentage were obtained from EDX. The saturation magnetization showed an increasing trend with increasing Cu concentration at a certain level and then decreases due to the rearrangement of cations at tetrahedral and octahedral sites. The Coercivity, Retentivity and magnetic crystalline anisotropy increase with changing dopant concentration. The magnetic measurements showed enhanced saturation magnetization at certain level (28.96emu/gm) and increase in coercivity up to 1102 Oe with changing dopant concentration. The estimated band gap energy is found to increase with Cu content. The dielectric constant, dielectric loss and impedance show normal behavior of ferrite. The frequency dependent dielectric constant decrease and tan delta shows a relaxation behavior at low frequencies. The synthesized nano Mg–Cu nanoparticles will be applied as humidity sensor, gas sensor, microwave devices and photocatalyst.

A remarkable permeability enhancement of Ni1−xZnxFe2O4 (x = 0.65 and 0.70), using a multi-compound calcined additive

In this study, entanglement of composition, additive and/or sintering conditions and their effects on magnetic properties of soft ferrites, nickel zinc spinel ferrites (Ni1−xZnxFe2O4, x = 0.65 and 0.70) which were prepared via conventional solid-state reaction method investigated. Also an equiponderant calcined mixture of Bi2O3, CaO, CeO2, SiO2, Al2O3, Y2O3 and nanotitania was mixed thoroughly and used as a multi-compound calcined additive (MCCA). Calcined ferrite powders were crushed, dry and wet milled, dried, mixed with different amounts of MCCA (0.0, 0.5, 1.0, 1.5 and 2.0 wt%), formed in toroidal shapes and finally sintered at different temperatures, from 1150 up to 1360 °C for 3 h. X-ray diffraction assessment confirmed formation of the single phase cubic spinel structures. Initial permeability and Q-factor spectra of the toroids were obtained from 0.1 to 1000 kHz, using an LCR meter. The results show that initial permeability of each sample has a maximum and addition of MCCA to the ferrites leads to a marvelous increase in permeabilities. Additionally, MCCA decreases the optimum sintering temperature too. The optimum amounts of additive were 1.0 and 0.5 wt% for the x = 0.65 (μ′ = 492, Ts = 1280 °C) and x = 0.70 (μ′ = 478, Ts = 1320 °C), respectively. Permeability spectra illustrate that utility zone of the Ni0.35Zn0.65Fe2O4 and Ni0.3Zn0.7Fe2O4 are both less than 100 and 10 kHz, respectively. The results represent that there is a strong entanglement between composition, additive and/or sintering conditions. It can be concluded the MCCA added Ni0.35Zn0.65Fe2O4, is suitable for application in the switching power supplies.

Recovery of Ni-Co-Mn Oxides from End-of-Life Lithium-Ion Batteries for the Application of a Negative Temperature Coefficient Sensor

This study demonstrates the current advancements in battery management systems (BMSs), emphasizing the need for precise temperature monitoring within battery packs to enhance safety and performance through efficient thermal management. The increased demand for lithium-ion batteries (LIBs) has driven the development of temperature sensors with improved accuracy and stability. In particular, Ni-Co-Mn-based spinel oxides are commonly used due to their stable negative temperature coefficient (NTC) behavior. However, challenges arise in manufacturing due to the high cost and uncertain supply of critical cathode components (e.g., Co, Ni, and Mn) for LIBs. This research focuses on developing spinel-type (Ni0.6Co0.4Mn2)O4 using recycled Ni-Co-Mn oxides obtained from end-of-life (EOL) LIBs, demonstrating temperature resistance behavior suitable for temperature sensing. The oxides are prepared through hydrometallurgy, oxalate synthesis, and post-heat treatment. Successful integration into spinel-type NTC thermistors suggests broader applications in various industrial fields. A systematic investigation into the synthesis and characterization of recovered Ni-Co-Mn oxides from EOL LIB cathode materials (Li(Ni0.33Co0.33Mn0.33)O2) is presented for NTC thermistor application. Thermogravimetric analysis-derivative thermogravimetry (TGA-DTG) identifies the optimal post-heat treatment temperature. The X-ray diffraction (XRD) patterns confirm a cubic spinel structure of the Ni-Co-Mn oxides, supported by scanning electron microscope (SEM) images showing a uniform microstructure. Also, energy dispersive X-ray spectroscopy (EDS) mapping confirms homogeneous element distribution. Recovered oxide pellets from the sintering process exhibit a single spinel structure, with X-ray photoelectron spectroscopy (XPS) analysis revealing changes in the valence states for Ni and Mn. Resistivity measurements demonstrate semiconductive behavior, which shows a B value (3376.92 K) suitable for NTC thermistor applications. This study contributes valuable insights to black powder recycling from EOL LIBs and its potential in temperature-sensitive electronic devices.

Structural and temperature dependent dielectric behaviour of BxFe(3−x)O4 nanoferrite particles

AbstractThe auto‐combustion technique was employed to synthesize nano particles of BxFe(3−x)O4 (x = 0.0, 0.7, 1.18, 1.36 and 1.54). The resulting structural and dielectric properties of the boron doped Fe3O4 were evaluated. XRD analysis confirmed the presence of a single spinel structure with crystallite dimensions ranging from 21.18 to 26.43 nm and lattice parameters of 8.211 to 8.487 Ǻ. The morphological images revealed homogenous and spherical grain sizes, while EDX confirmed the presence of constituent elements used. The X‐ray density increased whereas the bulk density and the porosity decreased with boron substitution. The study of dielectric properties and AC conductivity (σAC) was demonstrated and the AC conductivity decreased with increasing boron concentration, indicating a hopping mechanism. Moreover, noticeable variations in dielectric loss, AC conductivity, and dielectric permittivity with temperature and frequency were observed. These observations were attributed to the Maxwell–Wagner interfacial polarization and the hopping of charges between Fe3+ and Fe2+ ions.

Study of microstructure, magnetic and gas sensing properties of porous Ni0.4+xZn0.6-xCeyFe2-yO4 magnetic nanoparticles

The spinel ferrite systemsNi0.4+xZn0.6−xCeyFe2−yO4 (0≤x+y≤0.3) were synthesized by a modified glycol-thermal technique. X-ray diffractometer (XRD) confirmed formation of single phase cubic spinel structure with average crystallite sizes 8–21 nm. The crystallite sizes were found to be in agreement with the particle sizes obtained from the high resolution transmission electron microscopy (HRTEM) indicating formation of single domain nanoparticles. Scanning electron microscopy (SEM) showed a homogeneous spread of semi-spherical nanoparticles. Brunauer-Emmett-Teller (BET) revealed specific surface area ranging between 64 and 108 m2/g, while Barrett-Joyner-Halenda (BJH) showed the pore sizes varying between 48 and 126 nm. Cation distribution obtained from Rietveld refinement revealed all Ce3+ occupied B- sites whilst Ni2+, Zn2+, Fe3+ occupied both A and B sites. Magnetization measurements were performed using the vibration samples magnetometer (VSM). The saturation magnetization varied between 51 and 60 emu/g, while the coercivity dropped from 114 to 89Oe. The remnant magnetization varied between 3 and 12 emu/g. A correlation was observed between the saturation magnetization and the effective magnetic moments confirming cation distribution to be reliable. A strong correlation between initial susceptibility and unit cell volume was found. The crystallite sizes varied inversely with initial magnetic susceptibility. The magnetic characteristics of presented materials make them useful in high frequency device applications and has potential use as contrast agent in magnetic resonance imaging (MRI). 57Fe Mössbauer spectroscopy revealed the strengthening of ferromagnetic coupling. Gas sensing tests revealed a decrease in sensing response with the transition from paramagnetic state to ferromagnetic state. The Ni0.4Zn0.6Fe2O4 sample showed the best sensing response to SO2 at 100 °C compared to CO gas. However, at 150 °C the sample was more sensitive to CO gas than SO2 gas.

High-entropy (Co0.2Mn0.2Fe0.2Zn0.2Al0.2)3O4 thick-film NTC thermistor with high aging stability and wide temperature measurement range

Here, a novel type of high-entropy (Co0.2Mn0.2Fe0.2Zn0.2Al0.2)3O4 solid-solution ceramics with spinel phase structure was designed and successfully fabricated based on an entropy engineering approach. Additionally, the impact of sintering temperature, a critical factor in entropy stabilization, on structural and electrical behavior was systematically examined at a range of 1110∼1150 °C. The results indicate that each synthesized sample exhibits a single spinel structure in the Fd‾3 m (227) space group, and all five metal elements were uniformly distributed, demonstrating entropy stabilization. Meanwhile, the fabricated high-entropy ceramics manifest exceptional negative temperature coefficient (NTC) characteristics in the temperature range of 25 °C–350 °C. The aging stability is excellent as well. After aging at 150 °C for 1000 h, the ΔR/R0 of thick-film samples sintered at 1150 °C is less than 1 %. The successful synthesis of this novel class of spinel-type high-entropy ceramics introduces an emerging design approach for the development of NTC thermistors, particularly for applications in medium-temperature environments.

Tuning the gas sensing properties of spinel ferrite NiFe2O4 nanoparticles by Cu doping

Copper substituted nickel ferrite nanoparticles (NiFe2O4) nanoparticles were prepared using hydrothermal technique at lower reaction temperature (175 °C). The structural, optical, dielectric, and magnetic properties were analyzed. The prepared nanopowders exhibited single phase-cubic spinel structure with a mean crystallite size in a narrow range 30–41 nm. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the presence of stretching vibration of metal oxide in the range 400–600 nm. Field Emission Scanning Electron Microscopy (FESEM) and High Resolution-Transmission Electron Microscopy (HR-TEM) observations showed non-uniform cuboidal shaped nano-sized particles. The chemical and oxidation state of the constituents were revealed by X-ray photoelectron spectroscopy (XPS) (Cu2+, Fe3+ and Ni2+). Mössbauer spectra manifested two sextet patterns attributed to tetrahedral (A) and octahedral (B) sites with a doublet pattern of low intensity. Magnetic measurement revealed the decrease of saturation magnetization (Ms) value and increase of remanence magnetization (Mr) and coercivity (Hc) values while doping. A higher specific capacitance was obtained for x = 0.5 (1417 F/g) with a pseudocapacitive behavior. At room temperature, Liquefied Petroleum Gas (LPG) showed high selective response (1300 s for 250 ppm) compared to other tested gases.

Synthesis of ferromagnetic material nano powder and study of its effect on antibacterial activity

This work is to synthesize the cobalt ferrites nano powder of with the stoichiometric formula CoxFe2O4 (x= 0.8 and 1.4) by using sol-gel auto combustion method , and study structural and magnetic properties, the ferrite powders were calcined at 500, 600, and 700 °C for 3 hrs to remove organic waste and increase homogeneity and, The XRD diffraction analysis for CoxFe2O4 nanoferrites with single spinel structure. The crystal size of the formed crystallite of ferrite specimens increases with increasing temperature calcination and cobalt content , (FE-SEM) shows agglomerated with homogenous spherical and polyhedral particles. proportion of each of Fe ,Co, and O in all specimens is confirmed using the Energy Dispersive Spectrum (EDS),the magnetic characteristics are measured with a VSM. The remanence magnetization (Mr) saturation magnetization(Ms), and magnetic moment (nB) of CoxFe2O4 nanoferrites are found to go up with increasing calcination temperature, and E-coli bacteria were used to examine the inhibition of each ferrite using the diffusion-drilling agar method, as it is known that these nano powder possess therapeutic efficacy for numerous diseases.

Dielectric behavior of Zr4+ doped MgFe2O4 spinel ferrite synthesized by solid-state reaction method

A series of Zr4+ doped MgFe2O4 samples (Mg1-xFe2O4: xZr (x = 0, 0.25, 0.5, 0.75, 1, 1.25 and 1.5 mol %) were synthesized using the solid-state reaction method. The XRD analysis confirms that the prepared sample has single phase cubic spinel structure with Fd-3m space group. The average crystallite size of the sample has been found to be 28.2 nm. The SEM image shows irregular cubical grains with agglomerated morphology, while the EDX spectrum confirms the presence of all essential elements. The dielectric constant and dielectric loss decrease at higher frequencies due to decreased polarization. The Complex impedance spectroscopy confirmed the existence of electrical relaxation phenomenon, and the Cole-Cole plot indicates the grain boundary contribution. The AC conductivity value remains constant at a low frequency range but shifts towards the higher value in the higher frequency region. The calculated activation energy values range from 0.27 to 0.55 eV.

Mechanical strength and microwave dielectric properties of Al2O3 doped Li2MgTi3O8 ceramics with high temperature stability

A temperature stability microwave dielectric ceramic with composition of Li2MgTi3O8 (LMT) and Al2O3 with high flexural strength is synthesized by a conventional solid-state reaction method. The effects of Al2O3 (particles and whiskers) doping on the mechanical and dielectric properties of LMT ceramics are studied. A single spinel structure, without any secondary phases, is detected in the Al2O3 particles and Al2O3 whiskers doped LMT ceramics. The maximum flexural strengths of 152.5 MPa and 166.73 MPa are delivered in LMT +0.3 wt% Al2O3 (p) ceramics and LMT + 0.3 wt% Al2O3 (w) ceramics, respectively, which are enhanced by 53.21% and 67.52% over those of unmodified LMT ceramics. Pinning and grain refinement contribute to the enhanced flexural strength of the system. The intrinsic factors of Q × f change are analyzed by calculating the packing fraction and lattice energy. In addition, ceramics exhibit excellent comprehensive microwave properties at 1050 °C: (LMT + 0.2 wt% Al2O3 (p):Q × f = 67056 GHz, τf = −8.25 ppm/°C, εr = 24.34, σf = 133.3 MPa; LMT + 0.1 wt% Al2O3(w): Q × f = 68670 GHz, τf = −8.94 ppm/°C, εr = 24.32, σf = 122.7 MPa) The results indicate that Al2O3 particles and Al2O3 whiskers are decent reinforcing agents for LMT ceramics.

Enhancing removal of pollutants from pharmaceutical wastewater using ferrites in Membrane Bioreactor: A promising technology for environmental sustainability

Industrial wastewater contains various toxic and hazardous pollutants that require effective treatment to meet environmental regulations. In recent years, silver-doped ferrites have gained attention as promising materials for the treatment of industrial wastewater in membrane bioreactor (MBR). In this abstract, we will discuss the potential of silver-doped nickel ferrite (AgNiFe2O4) and silver-doped potassium ferrite (AgKFe2O4) was synthesized by sol-gel technique for the removal of pollutants from industrial wastewater. AgNiFe2O4 and AgKFe2O4 nanoparticles have been found to be effective for the removal of various pollutants, including heavy metals, organic compounds, and dyes, from industrial wastewater. Several studies have reported the successful application of silver-doped ferrites for the treatment of industrial wastewater. X-ray diffraction (XRD) pattern reveals the single phase cubic spinel structure with space group Fd-3m and Scanning electron microscope (SEM) confirmed the surface morphology of the synthesized nanoferrites. The use of AgNiFe2O4 and AgKFe2O4 has been found to significantly reduce the concentration of pollutants in wastewater, making it suitable for safe discharge into the environment. Furthermore, the regeneration of silver-doped ferrites has been found to be simple and cost-effective, making them an attractive alternative to conventional wastewater treatment methods. In conclusion, silver-doped nickel ferrite and silver-doped potassium ferrite have shown great potential for the treatment of pharmaceutical wastewater in MBR technique and ferrite materials make them promising candidates for future wastewater treatment technologies.

Carbonaceous MnFe2O4 nano-adsorbent: Synthesis, characterisation and investigations on chromium (VI) ions removal efficiency from aqueous solution

Carbonaceous manganese ferrite nanoparticles were prepared at relatively lower temperature using co-precipitation method followed by a single-step pyrolysis process. Synthesized nanoparticles were further characterized by different spectroscopic and microscopic techniques. The X-ray Diffraction (XRD) study confirmed the formation of single phase cubic spinel structure and the presence of graphitic carbon of plane (002) and the size of the prepared nanostructure was of 36 nm. With the confirmation of formation of carbonaceous MnFe2O4 and the number of oxygen functionalities such as hydroxyl and C-O-C groups emanating from the carbon matrix, as confirmed by the Fourier Transform Infrared (FT-IR) studies motivated their usage to remove Cr (VI) ions from aqueous solution. The study parameters such as influence of time, adsorbent dosage, concentration and pH are explored along with isotherm and kinetic studies. The carbonaceous nanoparticle was able to remove Cr (VI) by ∼80% at native pH, with a carbonaceous MnFe2O4 dose of 10 mg, and the initial concentration 10 ppm of contaminant with the contact time, 80 min and is found promising for the practical applications.

Superparamagnetic properties of iron oxide nanoparticles using vitex negundo leaf extract by green synthesis method and its antimicrobial activity against wound pathogen

Now-a-days green synthesis method is used to prepare the nanoparticles because of its non-toxicity and echo friendly nature. So we are focus the green synthesis method to make iron oxide nanoparticles from vitex negundo leaf extract. The prepared nanoparticles crystal structure, functional, morphology and elemental studies are analyzed by using X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX). The occurrence of a single phase cubic spinel structure with excellent purity is clearly demonstrated by the XRD. To determine the average crystallite size, the Debye Scherrer formula is employed. The created nanoparticles are used in biomedical applications and feature a superparamagnetic characteristic. SEM gives the agglomerated image. EDX has confirmed the existence of Fe and O elemental composition. The phytochemical studies are carried out for the vitex negundo leaf extract, such as flavonoids and terpenoids are present. The strong peak between 582 cm−1 in FTIR spectra is seen and is related to the characteristics of magnetite nanoparticles. Investigations of the antibacterial properties of iron oxide nanoparticles against staphylococcus sp. utilising the well diffusion method. The highest zone of clearance was observed at 100 µg/mL (2 mm).

Low-cost, ecofriendly, and large-scale synthesis of nanostructured Co1−xMnxFe2O4 microgranules with enhanced magnetic performance by chemical spray drying processing

We report, for the first time, the low-cost, eco-friendly, and large-scale synthesis of spray-drying production of Mn-substituted CoFe2O4 (Co1−xMnxFe2O4; x = 0.0–0.2; CMF) microgranules and their structural, morphological, and magnetic properties and performance characteristics in detail. The comprehensive study explored the intimate relationships between cation disorder or inversion degree due to Mn substitution in CoFe2O4 (CF) microgranules and corresponding changes in the structural and magnetic properties. Crystal structure and morphology studies indicate the formation of spherical shape, single cubic mixed inverse spinel structure of all the CMFO- microgranules with a size variation in the range of ⁓6.5–7.5 µm. Small angle X-ray scattering analyses indicate that the nanostructured CMF microgranules exhibit a virtually hard-sphere-like interaction. It is concluded that distortions are related to Co ions at octahedral locations due to Mn substitution in all materials. Raman spectroscopic studies, which corroborate with other structural studies, also reveal that replacing Co with Mn increases the degree of inversion in the cubic inverse spinel structure. Divalent (Co2+, Mn2+) and trivalent (Fe3+, Mn3+) cations are distributed differently across tetrahedral and octahedral sites. In addition to large-scale chemical synthesis, our results demonstrate the enhanced magnetic saturation from 82.27 to 86.18 emu/gm and 77.05–79.87 emu/gm for Co0.9Mn0.1Fe2O4 at 10 K and 300 K, respectively. In order for the proposed architectural design to serve as a crucial building block for a wide range of technological applications and be applicable to a large class of spinel ferrites, we present our attempt to draw the necessary fundamental scientific explanation from the trends in the local structural parameters and magnetic characteristics of CMF nanomaterials.

Highly Improved Acetone Gas Sensing Performance of Mesoporous Cobaltosic Oxide Nanoparticles and Physical Mechanism

Mesoporous Cobaltosic oxide nanoparticles are now widely employed in a variety of applications across the world. It is both environmentally and economically favorable. It was well prepared in this study using a cost-effective thermal stirring procedure. The X-ray diffraction method at ambient temperature was used to explain the formation of single spinel structure, purity, and cat-ion distribution of the material, and the lattice constant of mesoporous Cobaltosic oxide nanoparticles was 8.23 Å. SEM and EDX examination were used to investigate phase formation, elemental content, and surface morphology. The average particle size for primitive mesoporous Cobaltosic oxide nanoparticles is 17nm. DRS determined the band gap for mesoporous Cobaltosic oxide nanoparticles to be 1.48 eV for direct band bending and 2.19 eV for indirect band gap. The sensitivities of the sample are greater due to the mesoporous-structures with a large surface area. Mesoporous Cobaltosic oxide nanoparticles have a greater specific surface area (59.63m2 g− 1), resulting in good acetone gas sensing characteristics at the optimal working temperature of 150°C. Furthermore, the sample exhibits high stability and selectivity against acetone gas. The gas-sensing mechanism is determined by comparing the sensitivity of Mesoporous Cobaltosic oxide nanoparticles to surface oxygen and acetone gas adsorption. It is the best among the top other materials, according to the results.

Influence of V<SUB>2</SUB>O<SUB>5</SUB> Addition on the Magnetic Properties of Li-Zn Ferrites

The structural property, bulk density and porosity of V₂OSUB5/SUB (0.0, 0.4, 0.8 and 1.2 wt.%) added Li-Zn ferrites are observed along with the surface morphology. The samples have been prepared by the solid-state reaction technique and sintered at 1050 ℃. The X-ray diffraction patterns of the prepared samples have shown the single phase cubic spinel structure. A microstructural study demonstrates that the grain size increases up to 0.8 wt.% V₂OSUB5/SUB and slightly decreased thereafter for 1.2 wt.% V₂OSUB5/SUB addition. The saturation magnetization value increases from 44.0 to 50.3 emu/g as the V₂OSUB5/SUB content increases up to 0.8 wt.%. The decrease of magnetization for 1.2 wt.% V2O5 content is apparent and it is found to be 47.3 emu/g. This may be related to the dilution effect with the excess of non-magnetic V2O5. It is also observed that the value of initial permeability increases up to 0.8 wt.% V₂OSUB5/SUB.

Magnetic, optoelectronic, and rietveld refined structural properties of Al3+ substituted nanocrystalline Ni-Cu spinel ferrites: An experimental and DFT based study

The nanocrystalline Ni0.7Cu0.3AlxFe2-xO4 (x = 0.00: 0.02: 0.10) are prepared through the sol–gel auto combustion route. The structural, surface morphology, magnetic and optoelectronic properties of Al3+ substituted Ni-Cu spinel ferrites have been reported. The crystallinity, phase structure, and structural parameters of the synthesized nanoparticles (NPs) have been determined through X-ray diffraction (XRD) and further refined by maneuvering the Rietveld refinement approach. Both XRD and Rietveld confirm the single phase cubic spinel structure of the investigated materials. Microstructural surface morphology study also confirms the formation of NPs in the highly crystalline state with a narrow size distribution. The Rietveld-refined average crystallite size of the Al3+ doped Ni-Cu ferrite nanoparticles falls in the range (61–71 nm), and the average grain size is found to vary from 59 to 65 nm. All other structural parameters refined by the Rietveld refinement analysis are corroborated to single-phase cubic spinel formation of the NPs. Leveraging a vibrating sample magnetometer (VSM), the consequence of Al3+ substitution on the magnetic parameters is studied. The saturation magnetization (MS) and Bohr magneton are found to decrease with Al3+ substitution. The Remanence ratio and coercivity (HC) are observed to be very low, suggesting the materials are soft ferromagnetic. First-principle calculations were carried out using the density functional theory (DFT) to demonstrate the optoelectronic behavior of the materials. The electronic bandgap is found low as Eg = 2.99 eV for the explored materials with observing defect states at 0.62 eV. The optoelectronic properties of Al3+ substituted Ni-Cu ferrite NPs have been characterized through the DFT simulation for the first time, demonstrating their potentiality for optoelectronic device applications. The materials' optical anisotropy is observed along the x-axis, which manifests their tunability through light-matter interaction.