Ms Values Research Articles

Structural, dielectric and magnetic properties of terbium doped strontium spinel ferrite (SrFe2O4) synthesized by sol-gel method

In this research work, sol-gel technique was employed to prepare the strontium based spinel ferrite nanoparticles (SrFe2O4) with different ratios of terbium (Tb). Different characterization techniques were used to investigate the structural, morphological, dielectric and magnetic properties of the prepared samples. X-ray diffraction (XRD) result suggests that face-centered cube spinel nanocrystalline structure is formed. Crystallite size of the SrFe2O4 decreases with rising of Tb ratio. The morphology, shape and size of the SrFe2O4 were examined by scanning electron microscopy (SEM) analysis and results reveal inhomogeneous distributions of the nanostructures with high agglomeration. The electrical resistivity of the SrFe2O4 increases with rising of Tb ratio, which is confirmed from the cyclic voltammetry. It is observed that dielectric constant of all the samples decreases with increasing the frequency range. It is determined that the dielectric constants of the spinel ferrites are frequency dependent and decrease with increasing the frequency of applied electric field. The magnetic behavior of SrFe2O4 with different ratios of Tb was studied and it is found that the saturation magnetization values of samples decrease with increase in the substitution of Tb3+ at octahedral sites for Fe3+. This decrease in the values of Ms is also attributed to spin at surface of nanoparticles.

Structural and Magnetic Properties of MnxZn1-xFe2O4 Prepared via Sol-Gel Method

Manganese-zinc ferrite MnxZn1-xFe2O4 (MnZnF) powder was prepared using the sol-gel method. The morphological, structural, and magnetic properties of MnZnF powder were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray (EDX), field emission-scanning electron microscopes (FE-SEM), and vibrating sample magnetometers (VSM). The XRD results showed that the MnxZn1-xFe2O4 that was formed had a trigonal crystalline structure. AFM results showed that the average diameter of Manganese-Zinc Ferrite is 55.35 nm, indicating that the sample has a nanostructure dimension. The EDX spectrum revealed the presence of transition metals (Mn, Fe, Zn, and O) in Manganese-Zinc Ferrite. The FE-SEM results of MnZnF showed uniform spherical structures. VSM was used to study the change in magnetization, the saturation magnetization, (Ms) value of the samples. The measurement of VSM indicated that the MnZnF exhibits ferromagnetic behavior with coercivity Hc (0.0014 Gauss), remanent magnetization (Mr) (0.202 emu/gr), and saturation magnetization Ms (2.69 emu/g).

Study on the relationship between flavor components and quality of ice wine during freezing and brewing of 'beibinghong' grapes

Ice wine has prominent fruity sweetness and unique, rich aroma compared to wine. The sweetness was accumulating, the acidity and astringency tended to soften of grape berry during the freezing period. The process gave the ice wine balanced taste, with prominent honey sweetness, accompanied by refreshing alcoholic taste, soft acidity and astringency. Eleven key aroma compounds were identified in ice wine through GC–MS and ROAV values. The key aroma compounds were analyzed with Pearson correlation coefficient and fragrance mechanism were speculated. Ethyl acetate and 1-octen-3-ol derived from the aroma of grape, are produced by anaerobic metabolism and lipoxygenase pathways of pyruvate and linoleic acid, respectively. Ester aromas, 2-phenylethanol and 2-methylbutanal were derived from the brewing process, were produced by octanoic acid, caproic acid, phenylalanine and isoleucine through lipid metabolism, Ehrlich pathway and Strecker pathway, respectively. Proposed corresponding control methods based on factors that affect the formation of ice wine aromas.

Investigation and treatment of carbon pollution in LiZn ferrite ceramics prepared by spark plasma sintering

In this study, lithium–zinc ferrite (LZF) ceramics were prepared by spark plasma sintering. Problem of carbon pollution was effectively resolved by annealing decarburization, formation of BN-coated carbon paper, and formation of protective layer of different metal foils (Ti, Mo, W, and Ta). The effects of carbon pollution and different protective layers on microstructure and dielectric and magnetic properties of LZF ceramics were studied comprehensively. Results reveal that annealing decarburization and BN-coated carbon paper could significantly improve resistance and saturation magnetization (Ms) of LZF, while real part of dielectric constant (ε′) and dielectric loss (tanδ) were significantly reduced. X-ray diffraction patterns indicate that all selected protective layers can provide good spinel-phase LZF ceramics. The utilization of metallic foil as protective layer can effectively reduce carburization, improve the resistance of LZF ceramics, and reduce ε′ and tanδ values. X-ray photoemission spectroscopy and Raman spectroscopy results reveal that cations with the highest valence state replace Fe3+ at B-site. The use of metal foil protective layer leads to the infiltration of metal ions into LZF lattice, leading to the increase in the lattice constant and decrease in the Ms value. This study deepens the understanding of carburization during SPS, providing a reference scheme for future applications.

Structure, optical and magnetic properties of PVA/CuO/CoFe2O4 nanocomposite films for flexible magneto-electronic applications

Pure polyvinyl alcohol (PVA) and its nanocomposites with CuO and/or CoFe2O4 films have been prepared with different weights of ≤ 5 %. The structure of the films shows an orthorhombic phase of semi-crystalline polymer for PVA, a monoclinic phase for CuO, and a cubic phase of CoFe2O4 in nanocomposite films with particle sizes ≤ 25.5 nm, as determined by the XRD technique. Surface morphology by TEM of representative films shows the crystalline structure and nanoparticles and nanorods of individual CuO and/or CoFe2O4 compounds. The optical transmission and reflection properties of films have been measured, and the optical band gap has been estimated, showing that variable values (1.4–4 eV) can be controlled by controlling the percentage of CuO and/or CoFe2O4 in films. Magnetic investigation shows diamagnetic behavior for PVA and paramagnetic behavior for PC1, PC3, while PC5 has a very weak ferromagnetic response. Whereas nanocomposites with different contents of CoFe2O4 exhibit smooth ferromagnetic behavior with increasing Ms values. Ferromagnetic behavior has been confirmed via a convex Arrott–Belov–Kouvel plot. The improvement of magnetic properties makes the prepared films suitable to be used in various fields, such as antenna system miniaturization and flexible magneto-electronic applications.

Investigation of conventional exchange bias in (Nd1-xHox)2CoMnO6 (x = 0.0–0.4) double perovskite

In this article, we have investigated the characteristics related to structure, magnetism and exchange bias behavior in single phased polycrystalline samples of (Nd1-xHox)2CoMnO6 (x = 0.0–0.4) (NHCMO) series. The samples were prepared using the conventional solid state reaction technique and they crystalize in monoclinic structure with P21/n space group. The x = 0.0 sample shows the ferromagnetic transitions at TC1 = 139K and TC2 = 170K. These values decrease to 136K and 160K respectively for x = 0.1 sample. However, for other Ho substituted samples we observed only one transition. For x = 0.2, TC is 129K which decreases to 118K for x = 0.4 sample. The ferromagnetic super exchange interaction that arises within the network of Co2+ and Mn4+ ions bridged by O2− ions is the reason of occurring of these transitions. The presence of anti-site defects with antiferromagnetic interactions and subsequent formation of anti-phase boundaries within the system cannot be ignored. To gain a deeper insight into the underlying magnetic interactions, the M − T plots, under both the ZFC and FC conditions, were measured by applying different external magnetic fields. Saturation magnetization (MS) value of 3.68 μB/f.u. is observed in parent sample. The MS value increases to 7.22 μB/f.u. for x = 0.4 sample. Such mixed magnetic ground state of the samples motivates us to perform the exchange bias field measurement revealing an exchange bias field of 725Oe is found for x = 0.0 sample at 5K.

Regulation of microwave absorbing performance of magnetic alloy/ferrite/carbon ternary composites by changing polydopamine-induced carbothermal reduction

Magnetic alloy/ferrite/nitrogen-doped carbon composites (CoFe/CoFe2O4/N–C) spheres were synthesized by controlled carbothermal reduction of Co-doped Fe2O3 nanospheres wrapped in polydopamine. Different dopamine hydrochloride dosages not only affected components and nanostructures, but also regulated the electromagnetic properties of CoFe/CoFe2O4/N–C composites. The results show that with the increase of dopamine hydrochloride dosage, graphitic degree of N-doped carbon layer would decrease after an initial increase, while the Ms values exhibit an opposite trend. All samples show similar μr spectra, and negative μ″ values can be obtained at high frequency, which should be related to eddy current and dielectric resonance. With the increment of polydopamine, εr would first increase due to generation of CoFe and the increase in graphitic degree, and then decrease owing to the agglomeration of spherical particles. Further research on microwave absorption shows that RL peak frequency coincides with the frequency of perfect impedance matching when good impedance matching has been achieved across a wide range of frequencies. Thanks to the synergistic effects of conduction loss, interfacial polarization, dipole polarization, natural resonance, eddy current, and complete interference cancellation, S-100 has a wide effective absorption bandwidth of 4.88 GHz at 2.0 mm and a low RL peak value of −70.48 dB at 1.95 mm. This work could offer new insights into multi-component magnetic MAMs design and illuminate the relationships between reflection loss, impedance matching, interference cancellation, phase composition, and composite structure.

Selective occupancy of Fe substitution enhance the room-temperature ferromagnetism of (FexNi1-x)2P nanocrystals: Experimental and theoretical studies

Understanding the heteroatoms occupancy in metal phosphides is significant to regulate their properties. (FexNi1-x)2P (0 ≤ x ≤ 0.5) nanocrystals were prepared by thermal decomposition. Effects of Fe substitution on structure, morphology and magnetic properties were studied. As the Fe content increases, (FexNi1-x)2P maintain hexagonal structure with morphologies changing from sphere to irregular sheet. Atomic HAADF-STEM image reveals that the atom configuration matches well with [001] crystallographic orientation. (FexNi1-x)2P nanocrystals show room-temperature ferromagnetism. The Ms values and magnetocrystalline anisotropy are enhanced by increasing Fe substitution. The Ms value of (Fe0·5Ni0.5)2P reaches 2.092 emu/g, 19.5 times larger than Ni2P. XPS and Mössbauer spectra show that Fe2+/Fe3+ selectively occupy tetrahedral and pyramidal positions due to the difference of ionic radius, resulting in enhanced room-temperature ferromagnetism. First-principles calculations show that Fe substitution can induce ferromagnetic ordering in Ni2P, and Fe substitution in pyramidal positions induces larger magnetic moment, further confirming the experimental results.

Influence of Various Alloying Element Additions on Microstructure and Magnetic and Mechanical Properties and Corrosion Behavior of Cast Fe–Ga–Z Shape Memory Alloys

Fe–Ga alloys are attractive materials where high mechanical strength, toughness, ductility, and large low-field magnetostriction combine to give unique properties. Adding alloying elements is an effective method to further enhance these properties. In order to integrate these alloys into the operating environments, e.g., micro-robots and magnetic actuators, the corrosion behavior should be addressed. This work analyzed the microstructure, magnetization, hardness, and corrosion properties of Fe81Ga19−xZx (X = 5 at.% of Ni, Mn, or Ti, and 2 at.% Al; separately) alloys. X-ray diffraction (XRD), scanning electron microscope-electron (SEM), vibrating sample magnetometer (VSM), Vickers hardness (HV), and a potentiostat were used for characterization. XRD revealed that the prominent peak belongs to the bcc disorder A2 phase and a small peak for the cubic order L12 phase. Fe–Ga–Al alloy got the maximum Ms value, while Fe–Ga–Mn alloy gained the lowest one. However, the Mr and Hc properties for Fe–Ga alloy were distinctly improved by adding Al but slightly affected by doping Mn. Addition of Ti achieved the highest hardness, followed by Ni, Mn, and Al. The microstructure of the different alloys significantly influenced their corrosion behavior. Fe–Ga–Mn alloy with the fine globular grain structure showed the lowest corrosion rate (C R = 0.03 mm/year), whereas Fe–Ga–Al alloy with the coarse longitudinal grains exhibited the highest corrosion rate (C R = 0.19 mm/year).

Correlating pH-controlled green synthesis of NiO nanoparticles with their magnetic properties and catalytic performance

Nickel oxide nanoparticles (NiO) were prepared through environmentally friendly methods, using Nigella sativa seed extract as a stabilizing agent and different pH for the working solutions (pH=7, 9 and 11, respectively). In a second step, these NiO NPs were characterized with various and complementary techniques, as X-ray diffraction (XRD), Fourier transfer infrared spectroscopy (FTIR), Brunauer–Emmett–Teller method (BET), scanning electron microscopy (SEM) with EDS profiles, and a vibrating sample magnetometer (VSM). XRD patterns confirmed the one and only formation of NiO, as revealed by the Rietveld refinement procedure. The use of Williamson equation showed a significant variation in structural and microstructural parameters. Fourier transfer infrared spectroscopy (FTIR) analysis revealed vibration modes specific to Ni-O nanomaterials at 470 cm−1. On the other hand, magnetic investigations highlighted the fact that NiO, obtained in a solution with a pH equal to 9,called NiO-9, has the highest Ms and Mr values, of the order of 1.524 and 0.084 emu/g respectively, thus improving its ferromagnetic performance. Moreover, in the presence of NaBH4 and with the aim to reduce 4-nitrophenol to 4-aminophenol, in the case of water treatment, it appeared that the total time for the catalytic activity of NiO-9 was the lowest, i.e., 30 min. Moreover, NiO-9 was characterized by the faster rate constant, namely 0.29 min−1, which could be linked to intrinsic properties of this material (microstrain, electroactive sites and generated carrier charges).

Effect of The Composition of TiO2 Additives on The Physical and Magnetic Properties Crystal Structure and Microstructure of BaFe12O19 Magnetic Ceramics

<p>In this research, the manufacture of barium hexaferrite (BaFe<sub>12</sub>O<sub>19</sub>) magnetic ceramics and the addition of titanium dioxide (TiO<sub>2</sub>) additives with variations of 0%: 0.3%: 0.6% and 0.9% used the powder metallurgical method. The characterization used in this study is the measurement of density, porosity, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM), and Impulse Magnetizer K-Series. Based on the results of density and porosity measurements, the highest values were 4.95 g/cm3 and 5.45%, respectively. XRD results showed the formation of a BaFe<sub>12</sub>O<sub>19</sub> phase with some impurities at 0% (Fe<sub>2</sub>O<sub>3</sub>), 0.3% and 0.9% (Ti<sub>6</sub>O<sub>11</sub>), and 0.6% (Ti<sub>4</sub>O<sub>7</sub>). The SEM results showed that the morphology of TiO<sub>2</sub>-BaFe<sub>12</sub>O<sub>19</sub> was quite homogeneous, and the size and cavity ranged from 0.5 – 1.5 μm and 0.25 – 0.9 μm, respectively. VSM results show Mr, Ms, Hc, and Bhmax values of 1,489 kG, 3,235 kG, 1,758 kOe, and Bhmax of 0,867 MGOe, respectively. The results of the Impulse Magnetizer K-Series show the maximum and lowest magnetic flux values of 272.65 gauss and 218.10 gauss at 0.6% and 0% variation, respectively.</p>

Hydrothermal synthesis of high-purity zeolite X from coal fly ash for heavy metal removal: Kinetic and isotherm analysis

Treated fly ash (TCFA) yielded high-purity, single-phase zeolite-X, efficiently removing Ni and V ions from aqueous solutions. The pretreatment process of raw fly ash (RCFA) involved magnetic fraction separation, followed by acid washing. Zeolites were synthesized by the fusion prior step to the hydrothermal treatment method. The VSM test shows that the MS value dropped from 2.19 to 1.43 emu/g due to removing the magnetic fraction. These findings align with XRF results showing a 98 % reduction in Fe2O3 content, while acid washing lowered other metal oxide content to below 12 %. XRD results indicate the successful synthesis of high-crystallinity, single-phase zeolite X-TCFA, achieved at 90 °C for 12 h. SEM images further confirm the purity of the product, revealing pyramidal octahedral-shaped single crystals. Additionally, BET analysis shows a high surface area of 452 m2/g, featuring mesopores from 2 to 50 nm. The FTIR spectrum displayed the characteristic peaks of Zeolite X, confirming the success of the preparation process. TCFA-zeolite X has high thermal stability based on TGA analysis. The pseudo-second-order model fits the kinetic data, suggesting that chemical adsorption mechanisms control Ni and V adsorption. Langmuir isotherm best-explained results, with max adsorption of 41.55 mg/g Ni and 32.38 mg/g V.

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.

Structural, magnetic, and Mössbauer studies of magnetite and nickel-copper and nickel-zinc ferrites

This work aims to investigate the magnetite obtained by coprecipitation, as well as the mixed ferrites of nickel-copper and nickel-zinc. The as-prepared samples were then annealed at a temperature (Tan) of 1000 °C. The as-prepared magnetite shows a polycrystalline spinel structure having an average of crystallite size (DXRD) of 8 nm, while other as-prepared mixed ferrites are structurally amorphous. Annealing at Tan has resulted in an improvement in the crystallinity of both nickel-copper ferrites (NCF, DXRD = 92 nm) and nickel-zinc ferrites (NZF, DXRD = 83 nm), both of which exhibit a cubic spinel structure. The thermal treatment in air atmosphere has also led to the oxidation of magnetite into hematite. Morphological observations suggest that the magnetite nanoparticles are nearly spherical, whereas the NCF and NZF particles indicate irregular shapes, which tend to aggregate. Magnetic curves reveal that the NCF exhibits a blocking temperature (TB) close to room temperature, while the NZF sample displays the lowest TB at 45 K. Additionally, the NZF exhibits a higher Ms value of 80.4 emu/g and displays a narrow hysteresis loop, which makes it suitable for applications in hyperthermia. The 57Fe Mössbauer study on magnetite and NZF indicates broadening spectra, which is due to superparamagnetic relaxation, thus the fit their spectra was established with hyperfine field distribution component. Regarding the NCF Mössbauer spectrum was adjusted by superimposing two sextets reflecting the presence of Fe3+ at the A and B sites of spinel. The hyperfine parameters, including the isomer shift, and hyperfine field, have been systematically reported in the present study.

A Comparison of the Effect of Activator Cations (Sodium and Potassium) on the Fresh and Hardened Properties of Mine Tailing-Slag Binders

This study develops alkali-activated mine tailing (MT)-based binders containing MT as the major source material and slag (S) as a minor additive, using alkaline activators containing sodium or potassium as the cationic species. The influence of the cationic species (Na or K), slag content, alkalinity (expressed using the activator silica modulus, Ms), and alkali oxide-to-powder ratio, n, on the setting behavior, paste rheology, early-age reaction kinetics, and compressive strength development are discussed. The effects of using solid activators are also considered. Changes in Ms values have a stronger impact on setting times compared to n values, underscoring the significant role of silicate species from the activator in the initial reaction mechanisms. The type of cation and physical state of the activator (in the case of K–Si-activated systems) are found to determine the dissolution rate and mobility of ionic species in the system, resulting in significant differences in the early age reaction mechanisms (e.g., K-based activators show >2× enhancement in early heat release as compared to Na-based activators) of the alkali-activated binders prepared using the same activator parameters. The difference in the viscosities of the activator solutions strongly influences the rheological characteristics of the activated systems. MT-based binders with 28-day compressive strengths ranging from 10 to 35 MPa, which are suitable for several structural/non-structural applications, are attained. The strong dependence of the compressive strength development on the alkali activation parameters and slag content in the system presents an opportunity to develop sustainable binders, with MT as their major constituent, to provide twin benefits of recycling MT wastes and mitigating the environmental impacts associated with traditional ordinary Portland cement-based binder systems.

Relationship among intrinsic magnetic parameters and structure and crucial effect of metastable Fe3B phase in Fe-metalloid amorphous alloys

The intrinsic heterogeneity of an amorphous structure originates from composition, and the structure determines the magnetic properties and crystallization models of amorphous magnets. Based on classical Fe–B binary magnetic amorphous alloys, the relationship between the structure and magnetic properties was extensively studied. The stacking structure of Fe–B binary amorphous alloys exhibit discontinuous changes within the range of 74–87 at.% Fe. The structural feature can be expressed as Amor. Fe3B matrix + Fe atoms are transforming into Amor. Fe matrix + B atoms with the increase of Fe content. The solute atoms are uniformly distributed in the amorphous matrix holes, similar to a single-phase solid solution structure. The transition point corresponds to the eutectic crystallization model composition (Fe82B18 to Fe83B17). A high Fe content will amplify magnetic moment sensitivity to temperature. Under a given service temperature, the disturbance effect of magnetic moment self-spinning will offset the beneficial effect of increasing Fe content and induce the saturation magnetization (Ms) value to decrease. Binary amorphous Fe–B alloys obtain the maximum Curie temperature near 75 at.% Fe, which is slightly smaller than that of the corresponding metastable Fe3B phase, i.e., the amorphous short-range order structure maintains the highest similarity to the Fe3B phase. The chemical short-range ordering (SRO) structure of amorphous alloys exhibits heredity to corresponding (meta)stable crystal phases. The unique spatial orientation structure of the metastable Fe3B phase is the structural origin of the amorphous nature. This study can guide the composition design of Fe-metalloid magnetic amorphous alloys. The design of materials with excellent magnetic properties originates from a deep understanding of precise composition control and temperature disturbance mechanism.

Selectivity of β-Cyclodextrin Polymer toward Aquatic Contaminants: Insights from Ultrahigh-Resolution Mass Spectrometry of Dissolved Organic Matter.

Selectivity in solid-phase extraction (SPE) materials has become increasingly important for analyte enrichment in sensitive analytical workflows to alleviate detrimental matrix effects. Molecular-level investigation of matrix constituents, which are preferentially extracted or excluded, can provide the analytical chemist with valuable information to learn about their control on sorbent selectivity. In this work, we employ nontargeted Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) to elucidate the molecular chemodiversity of freshwater-derived dissolved organic matter (DOM) extracted by the selective model sorbent β-cyclodextrin polymer (β-CDP) in comparison to conventional, universal SPE sorbents (i.e., Oasis HLB, Supel-Select HLB, and LiChrolut EN). Statistical analysis of MS data corroborated the highly selective nature of β-CDP by revealing the extracted DOM spectra that are most dissimilar to original compositions. We found that its selectivity was characterized by pronounced discrimination against highly oxygenated and unsaturated DOM compounds, which were associated with the classes of lignin-like, tannin-like, and carboxylic-rich alicyclic molecules. In contrast, conventional sorbents excluded less highly oxygenated compounds and showed a more universal extraction behavior for a wide range of DOM compositional space. We lay these findings in a larger context that aids the analyst in obtaining an a priori estimate of sorbent selectivity toward any target analyte of interest serving thereby an optimization of sample preparation. This study highlights the great value of nontargeted ultrahigh-resolution MS for better understanding of targeted analytics and provides new insights into the selective sorption behavior of novel sorbents.

A novel magnetic NiFe2O4-Ag-ZnO hybrid nanocomposite for the escalated photocatalytic dye degradation and antibacterial activities

The eco-friendly and cost-effective NiFe2O4-Ag-ZnO (nickel ferrite-silver-zinc oxide) (NFAZnO) nanocomposite was made using an easy straightforward chemical co-precipitation method and subsequent thermal treatment process. The increased UV light-driven photocatalytic performance and enhanced antibacterial activity of the nanocomposite were reported. The structural, morphological, magnetic, and catalytic characteristics of the nanocomposite were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), photoluminescence (PL), Raman, vibrating-sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analysis. The results from XRD revealed that NFAZnO has a crystalline structure and EDAX elemental mapping confirmed the uniform distributed of all the elements in the matrix. Investigations into the microstructure found ultrafine grained structure of NFAZnO nanocomposite with an average crystallite size of 27.95 ± 0.38 nm as calculated from Scherrer’s formula. NFAZnO nanocomposite has a specific surface area of 13.56 m2/g, which is significantly more than ZnO (6.89 m2/g) as calculated from BET. At normal temperature, the magnetic characteristics showed the superparamagnetic behavior of the nanocomposite with saturation magnetization (Ms) value of 6.59 emu/g, remnant magnetization (Mr) value of 0.75 emu/g, and coercive field (Hc) value of 170 Oe. The Ag doping and addition of NiFe2O4 induces depletion in near-band edge emission, which lowers the rate of electron-hole recombination, according to the PL observations. Methylene Blue (MB) dye was subjected to photocatalytic degradation under the exposure to UV light, and according to the findings, NFAZnO nanocomposite exhibited the highest levels of photocatalytic activity with 98% degradation in just 60 min. The NFAZnO nanocomposite also showed enhanced antibacterial activity against Escherichia coli (E. coli) having zone of inhibition (ZOI) of about 28.9 ± 0.28 mm showing 123.5% activity as compared to control ampicillin having ZOI of 23.4 ± 0.13 mm, proving its applicability for both biomedical and environmental applications.

Evaluation of structural, optical, and magnetic properties of Gd doped MnFe2O4 nanoparticles

In this study, the MnFe2O4 doped Gd (MnGdxFe2-xO4 with x = 0, 0.125, 0.25, and 0.5) magnetic nanoparticles were successfully synthesized and revealed the significant effect of Gd content on structural, optical, and magnetic properties. The replacement of Fe3+ ions by ion Gd3+ ions changed the crystallite size from 8.2 nm (x = 0) to 13.5 nm (x = 0.5). The band gap of Gd-doped MnFe2O4 increased with an increase of the x value. The magnetic curves showed that saturation magnetization (MS) and magnetic anisotropy (K) decreased simultaneously with the concentration of Gd3+ ions. The MS value reduced from 54.0 emu/g (MnFe2O4) to 35.4 emu/g (MnGd0.5Fe1.5O4). The K value dropped from 50.4 kJ/m3 (MnGd0.125Fe1.875O4) to 12.3 kJ/m3 (MnGd0.5Fe1.5O4). The substantial reliance of magnetic anisotropy on the doping concentration, namely this large change in K with a little change in size (8.2 nm–13.5 nm), demonstrated that doping is a suitable method for modifying the values of magnetic anisotropy of materials.

Improved magnetic properties of Fe substituted La2CoMnO6 for spintronic applications

A detailed study of magnetic behaviour of double perovskites was carried out by developing La2Co1-xFexMnO6; (x = 0.0, 0.2, 0.5, 0.8 and 1.0) via sol–gel technique. All samples showed single magnetic transition except pure LCMO (x = 0.0) and LCFMO2 (x = 0.5). Temperature dependent inverse magnetic susceptibility (χ-1) was fitted in accordance with Curie-Weiss law. μeff (effective magnetic moment) was determined for all the developed samples. Pure LCMO showed a downward divergence from Curie-Weiss law below 230 K but above transition temperature which indicates the characteristics of Griffiths phase. Saturation magnetization (Ms) increased initially and then decreased, whereas coercive field (Hc) was found to be monotonous decreased with increase in Fe content. LCFMO1 (x = 0.2) was noticed to have maximum Ms (38.87 emu/g) which indicated that the magnetic properties of pure LCMO were improved with Fe substitution, but for lower substitution only. Magnetization vs. field (M−H) curves were not well saturated even at a magnetic field of 60 kOe, therefore, values of Ms for all the samples were estimated using law of approach to saturation. With increase in Fe content, an increased anti-site disorder among Mn and Co strengthened antiferromagnetic (AFM) super exchange interactions and weakened ferromagnetism (FM). Therefore, substitution of Fe on Co-site was responsible for systematic decrease in saturation magnetization when × exceeded 0.2.