Remanent Magnetization Values Research Articles

Nano to micron-size combustion particles in smokers’ homes: Magnetic properties of tobacco and cigarette ashes

Cigarette emission comprises high-temperature combustion processes producing diverse harmful compounds, gases, and particulate matter that are spread through the air and can be taken by smokers and passive smokers involuntarily. We determined the magnetic properties of tobacco cigarettes from six commercial brands. We also monitored the emission of particulate matter in some smokers’ homes using low-cost sensors and the PM2.5 dataset was studied through a time series analysis. In addition, compositional, morphological, and magnetic properties of cigarette ashes were studied and compared with available data. Unexpected positive mean values of specific magnetic susceptibility (χ = 3.7 × 10−8 m3kg−1) and saturation isothermal remanent magnetization (SIRM = 0.6×10−3 Am2kg−1) of tobacco cigarettes indicate the presence of “magnetic condiments” in this unburned material. In contrast, as a consequence of puff and smoldering burn, a magnetic increase of up to 35-fold the reference values of unburned material evidence an important neoformation of airborne tobacco-derived magnetic particle ToMP. Mixtures of these ToMPs with different sizes, from nano to micron-sized, comprise superparamagnetic SP, single-domain SD, and multidomain MD particles. This work provides new accurate information on specific tobacco product ingredients (not declared) and the unnoticed ToMP emission after smoking habits, which are needed for tobacco products, consumers and passive smokers (including vulnerable children) exposed to second-hand smoke. ToMPs and myriad other toxicants may be inhaled, escape from the inhalation system and penetrate biological barriers leading to long-term human health risks.

Synergetic effect of hexaferrite and reduced graphene oxide (rGO) in photothermal therapy and hyperthermia applications

This research article describes the synthesis of composite materials by combining T-type hexagonal ferrite and reduced Graphene Oxide using the standard ceramic process. The Calcium-based T-type hexagonal ferrite was synthesized by using the sol-gel auto-combustion method while the reduced graphene oxide by adopting the Hummer method. The crystallite size varied in the range of 23.38 -39.16 nm as calculated from the X-ray diffraction (XRD) data. Consequently, the lattice parameters 'a' and 'c' decreased from 5.9 to 5.1 Å and from 29.92 to 28.32 Å, respectively. The use of atomic force microscopy (AFM) revealed a range of particle sizes at the surface, varying from 1.70 nm to 3.85 nm. Moreover, the saturation and remanence magnetization values demonstrated an increasing trend with T-type hexaferrites concentration whereas the coercivity decreased. The UV–vis near-infrared spectra exhibited substantial light absorption, characterized by a wide absorption range in the visible and near-infrared (NIR) region (700–1100 nm) which indicates its use in Photothermal therapy (PTT). The Calcium T- type hexaferrite exhibited clear peaks in the blue, green, violet, and yellow spectra in its photoluminescence (PL) properties. These peaks are believed to be caused by oxygen vacancies and defects. The synthesized samples displayed a lossy behavior in the polarization-electric field (P-E) loop, with saturation polarization levels exceeding remnant polarization, which is an amenable condition for lossy behavior. Most importantly, the synthesized materials had significant thermal responses when exposed to an alternation (AC) magnetic field, indicating their potential use in magnetic hyperthermia applications.

Investigation of electrical, dielectric and multiferroic properties of 0.7Bi0.95Sm0.05Fe1-xGaxO3-0.3BaTiO3 composite ceramic system for high temperature piezoelectric applications

Lead-free composite ceramics, 0.7Bi0.95Sm0.05Fe1-xGaxO3-0.3BaTiO3 (BSFGx-BT), were made using a solid-state reaction method for x = 2.5, 5, 10, 15, and 20 %. We have investigated the effects of Samarium (Sm) and Gallium (Ga) co-doping on the crystal structure, topography, spectroscopy, electrical and multiferroic characteristics of the 0.7BiFeO3-0.3BaTiO3 (0.7BFO-0.3BTO) system for piezoelectric applications. The structural results indicate that the composite ceramics exhibited rhombohedra R and tetragonal T phases characterized by R3c and P4mm space groups, respectively which was also further confirmed by X-ray Rietveld refinement pattern analysis. In dielectric behaviour study high Curie temperature of 550 °C was obtained with high temperature stability. Furthermore, the study investigated the effects of grain and grain boundaries on capacitive and resistive properties. The ceramics displayed the characteristics of the negative temperature coefficient of resistance (NTCR). It was observed that as the Ga concentration increased, the grain resistance (Rb) also increased, reaching its maximum value for x =10 %. Additionally, at higher temperatures, this composite exhibited lower electrical resistivity. Importantly, the ceramics showed the co-existence of ferromagnetic and ferroelectric behaviour with the enhanced values of remanent magnetization (Mr)= 0.043 emu/g, coercivity (Hc) = 5730 Oe and remanent polarization (Pr) = 6.07 µC/cm2, coercive field (Ec) = 6.78 kV/cm for the composition x =10 %. These findings suggest that Sm & Ga incorporated 0.7BFO-0.3BTO composite ceramics can show promising high-temperature piezoelectric applications.

Effect of annealing temperature and precipitation agent on the structure, optical and magnetic characteristics of dysprosium orthoferrite nanoparticles

Powders consisting of DyFeO3 nanoparticles were obtained by the co-precipitation method using two different precipitating agents (NaOH (SH) and (NH4)2CO3 (AC) solutions) and followed by annealing for 1 h at 850, and 950 °C. Properties of the synthesized samples were characterized by FT-IR, PXRD, BET, TEM, UV-Vis DRS, and VSM analyses. The obtained data revealed that both calcination temperature and precipitation agent had notable influence on the structural parameters and properties of the synthesized DyFeO3 nanoparticles. Increasing the calcination temperature led to the increase of structural characteristics such as average crystallite size (DScher, DW-H, DRietveld, nm), lattice cell volume (V, Å), and crystallite phase content as well as in properties such as band gap energy value (Eg, eV), coercivity (Hc, Oe), remanent magnetization (Mr, emu∙g−1), and net magnetization (Mn, emu∙g−1). Additionally, when comparing samples calcined at the same temperature, DyFeO3-AC exhibited higher structural, optical, and magnetic properties compared to DyFeO3-SH. Moreover, the DyFeO3 nanoparticles synthesized in this study exhibited lower band gap energy (1.87–1.93 eV), coercivity (0.018–0.023 Oe), and remanent magnetization (2.82∙10−6–3.87∙10−6 emu∙g−1) values, but larger net magnetization (2.43–2.62 emu∙g−1) when compared to RFeO3 perovskites synthesized by different methods (R = La, Y, Ho, Dy, Eu, Tb).

The Effect of a Ferromagnetic Steel Enclosure on Magnetic Shielding Systems: Analysis, Modeling, and Experimental Validation

The magnetic shielding device, made of high-permeability soft magnetic material, is sensitive to external influences and requires a protective steel enclosure. A steel enclosure, being strongly ferrimagnetic, can alter the surrounding magnetic field distribution, thus impacting the shielding effectiveness. This study proposes a novel analytical approach to quantify this effect, which has not been previously researched. The method develops a simplified finite element simulation model based on the structural symmetry of the steel enclosure. By using this model, this study analyzes the impact of steel structures with varying heights, widths, and remanent magnetization values. The validity of the method is confirmed through experimental tests on steel buildings. The findings offer insights into the optimal placement of magnetic shielding systems and provide theoretical guidance for designing large-scale magnetic shielding devices.

Effect of divalent ion of strontium substitution on the structural, optical, magnetic and blood compatibility studies in cobalt ferrite

This study investigates the effects of Sr2+ substitution on the structural, morphological, and magnetic properties of magnetic cobalt ferrite (CoFe2O4). Through sol–gel auto-combustion synthesis, Sr2+ was substituted into Co-spinel ferrites (Co1-xSrxFe2O4, where x = 0.0, 0.25, 0.5, 0.75, 1.0). SEM analysis revealed spherical grains with an average size of 54.4 nm. XRD analysis indicated systematic changes in crystallographic parameters and the formation of secondary phases with Sr-substitution. While the crystal size for CoFe2O4 was calculated as 262 nm, this value was determined as 18 nm for Co0.25Sr0.75Fe2O4. FT-IR results suggested increased force constants of octahedral and tetrahedral bonds with higher Sr content, with main vibration bands at 423.6 and 606 cm−1. M-H curves exhibited S-shaped behavior, indicating drastic magnetic property changes with Sr2+ substitution. Coercivity field (Hc), saturation magnetization (M S ), and remanent magnetization (M r ) values ranged from 1447.8–545.4 Oe, 58.8-14 emu g−1, and 36.8-7.6 emu g−1, respectively. Blood compatibility experiments highlighted Co0.75Sr0.25Fe2O4 nanoparticles with significantly low hemolysis rates compared to other concentrations.

Magnetic, Optical, Electrical and Antimicrobial Properties of MnCuZnFe2O4 Nanoparticles

AbstractThe Mn0.92Cu0.08‐yZnyFe2O4 (y=0.02, 0.04, 0.06 and 0.08) nanoparticles (MCZF NPs) were synthesized via the hydrothermal process at low operating temperature. The MCZF system generated a cubic spinel structure as seen by the X‐ray diffraction patterns. The average crystallite size was observed to be increasing from 25 to 30 nm. The broad (γ1) and narrow (γ2) absorption bands were seen in FTIR spectra and the cation distributions at tetrahedral (A) and octahedral (B) sites, respectively, was indicated. The surface morphology was analyzed using electron microscopy. Clarification was provided for the dependence of the optical bandgap shift (Eg~1.96–2.15 eV) on the concentration of substituent. The superparamagnetic nature of MCZF can be advantageous for biomedical applications and it was demonstrated by the magnetization versus applied magnetic field (M−H) loops. Small values of remanence magnetization (Mr) and coercivity (Hc) were found using magnetization versus magnetic field (M−H) curves at y=0.02, 0.04, 0.06, and 0.08. This proved that MCZF NPs exhibited the superparamagnetic behavior. The cation distribution at two sublattices was also estimated using a two‐sublattice model. The greatest zone of inhibition in an antibacterial study of MCZF (produced by the green method) was 10.8 mm for Pseudomonosa aeruginosa and 9.4 mm for Staphylococcus aureus.

Adjusting the gas detection characteristics of NiFe2O4 spinel ferrite nanoparticles through the introduction of Zn doping

Nickel ferrite nanoparticles doped with zinc were synthesized at a lower reaction temperature of 180 °C. The research delved into their structural, optical, dielectric, and magnetic properties. These nanoparticles exhibited a distinct cubic spinel structure, with crystallite sizes ranging from 33 to 51 nm. FTIR analysis revealed metal oxide stretching vibrations between 400–600 nm. FESEM and HR-TEM examinations unveiled irregularly shaped nano-particles. XPS analysis disclosed the chemical states of Zn2+, Fe3+, and Ni2+ ions. Mossbauer spectra exhibited two sextet patterns related to tetrahedral (A) and octahedral (B) sites, plus a weak doublet pattern. Magnetic tests showed a decrease in saturation magnetization (Ms) but an increase in remanent magnetization (Mr) and coercivity (Hc) values upon doping.

Effect of Cu substitution on magnetic and photocatalytic properties of Mn–ZnFe2O4 nanoparticles

The citrate approach was employed to successfully synthesize Mn0.4Zn0.6−xCuxFe2O4 (MZCF) with a nanostructured shape. A thorough examination was conducted on the microstructural, magnetic, and optical properties of the nanoparticles obtained. The X-ray diffraction (XRD) patterns revealed that all of the compositions exhibit a high degree of single-phase spinel formation. The experimental findings indicate that the introduction of copper ions leads to a reduction in both lattice constant and porosity, while concurrently resulting in an increase in the theoretical X-ray and bulk densities. The analysis of UV–Vis spectroscopy indicated that MZCF exhibited a direct band gap falling within the range of 1.61–1.78 eV. The magnetic characteristics were assessed through the analysis of hysteresis plots. The introduction of copper (Cu) content leads to notable improvements in the saturation (Ms) and remanent magnetization (Mr) values, which range from 40.21 to 58.78 and 4.46–10.54 emu/g, respectively. The assessment of the microwave frequency response has verified the appropriateness of MZCF nanoferrites for application within the frequency spectrum spanning from 8 to 13 gigahertz. The nanoparticles exhibit improved magnetic properties, suggesting their potential appropriateness for applications involving high-frequency microwave absorption and switching. Furthermore, the nanoparticles Mn0.4Zn0.6Fe2O4 and Mn0.4Zn0.2Cu0.4Fe2O4 were subjected to analysis utilizing a solar light simulator in order to induce degradation of MB dye.

Lithographically Ordered FePt L10 Dots with High Coercivity for Logic-Conditioned Magnetic Nanostructures

In order to develop the building blocks for future biosensing and spintronic applications, an engraving technique using electron beam lithography is employed in order to develop nanomagnetic pre-patterned structures with logic potential. The paper describes the realization and morphological and magnetic characterization of potentially logic-conditioned substrates, a building block to be further used as an integration platform upon which nanodevices, such as magnetic wires, or various geometrical shapes, circles, triangles, can be considered as pre-requisite for full integration into logic devices. As a proof of concept, regular arrays of FePt circles or magnetic dots were devised and structural characterization by X-ray diffraction and transmission electron microscopy proved the occurrence of the tetragonal L10 phase. Moreover, the magnetic characterization provided more insight into the potential of such arrays of magnetic devices as the hysteresis provided good values of magnetic coercivity, remanent and saturation magnetization. These findings show good potential for developing regular arrays of uniformly shaped magnetic entities with encouraging magnetic performances in view of potential applications in various applications.

Highly Coercive L10-Phase Dots Obtained through Low Temperature Annealing for Nano-Logic Magnetic Structures

Nano-logic magnetic structures are of great interest for spintronic applications. While the methods used for developing arrays of magnetic L10-phase dots are, in most cases, based on deposition followed by annealing at high temperatures, usually around 700 °C, we demonstrate here a technique where a much lower annealing temperature (i.e., 400 °C) is needed in order to promote fully the disorder–order phase transformation and achievement of highly coercive L10-phase dots. In order to develop building blocks based on arrays of L10-phase FePt dots for further spintronic applications, an engraving technique using electron beam lithography is employed. This paper describes the fabrication, as well as the morphological and magnetic characterization, of regularly placed FePt dots of various shapes, as pre-requisites for integration into nano-logic devices. As a proof of concept, regular arrays of FePt circular dots were devised and their structural characterization, using X-ray diffraction (XRD) and transmission electron microscopy (TEM), was performed. It has been shown that annealing at only 400 °C for 30 min proved the occurrence of the tetragonal L10 phase. Moreover, structural characterization showed that the disorder–order phase transformation was complete with only the L10 phase detected in high resolution TEM. The magnetic characterization provided more insight into the potential of such arrays of magnetic devices with convenient values of magnetic coercivity, remanent and saturation magnetization. These findings show good potential for developing regular arrays of uniformly shaped magnetic entities with encouraging magnetic performances in view of various applications.

Magnetic characteristics of atmospheric particulate matter and its indication of atmospheric pollution during winter in Lanzhou, NW China

In order to elucidate the significance of environmental magnetic methods in monitoring atmospheric particulate matter pollution, this study conducted an analysis of the magnetic and chemical properties of PM10 and PM2.5 samples collected during winter in Lanzhou City. The magnetic measurements revealed significant variations in the saturation isothermal remanent magnetization (SIRM) values between daytime and nighttime, with higher SIRM values during nighttime. The magnetic properties were dominated by low-coercivity ferrimagnetic minerals exhibiting multidomain and pseudo-single domain characteristics. SIRM exhibited a significant correlation with the mass concentration of particulate matter. The correlation indicated that during the day, the SIRM of PM2.5 showed a significant correlation with elements such as Zn, Pb, Cl−, K+, K, and organic carbon (OC). Additionally, the SIRM of PM10 was also related to Mg2+, Ca2+, and some crustal elements. During nighttime, the SIRM of PM10 and PM2.5 was primarily associated with Cl−, K+, K, and OC. By comparing the magnetic and chemical properties of particulate matter under clean and non-clean air conditions, similar trends were observed between SIRM and indicators such as NO3−/SO42−, As/Pb, K+/K, and Ca2+, which are commonly associated with traffic emissions, biomass burning, and construction dust sources. Factor analysis was applied to further investigate the sources of magnetic particles, unequivocally demonstrating that traffic emissions constituted the primary source of magnetic particles in both PM10 and PM2.5 during daytime, whereas biomass burning emerged as the predominant source during nighttime. Consequently, our study highlights the innovative use of magnetic parameters as reliable indicators for assessing atmospheric particulate pollution and discerning the sources of particulate matter.

Investigation on bio-synthesized Ni- and Al-doped cobalt ferrite using lemon juice as eco-fuel

Pure and doped cobalt ferrite (CoFe2O4) nanoparticles were prepared using sol-gel auto-combustion route with the aid of lemon juice as eco-fuel. In this study, Ni2+ and Al3+ ions were chosen as the dopants. The cubic spinel crystal structure of the synthesized ferrite samples was elucidated from the powder X-ray diffraction analysis. The crystallographic parameters associated with the samples were obtained from the Rietveld profile refinement of the diffraction patterns. The precise lattice parameter obtained from the Nelson-Riley extrapolation method is found nearly matches with the lattice parameter obtained from the Rietveld refinement of respective samples. The average crystallite size and microstrain accompanying with the samples were estimated from various methods such as via the Debye-Scherrer method, Williamson-Hall analysis and size-strain plot. By employing Tauc’s plot method, the optical parameters such as the direct bandgap, sub-bandgap and the Urbach energy of all the samples were calculated by analyzing the UV-Visible reflectance spectra. The room temperature magnetic properties of all the samples were estimated from the vibrating sample magnetometry. The nature of magnetic hysteresis revealed the semi-hard ferrimagnetism of the prepared cobalt ferrite samples. Also, the variation of magnetic properties with doping was analyzed. The weakening of interaction among the ions in tetrahedral and octahedral sites causes a decrease in the values of remanent magnetization, saturation magnetization and coercivity of doped samples.

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.

The impact of Cu, Ni and Fe2O3 on the magnetic behavior and structural properties of FeSiO2 nanocomposite synthesized through ball milling

The nanocomposite Fe-A/SiO2 soft magnetic materials, with Cu, Ni, and Fe2O3 as dopants, were produced using a mechanical alloying technique. Our central objective was to explore the impact of process parameters on Fe/SiO2 nanocomposite properties. We assessed varying milling time and dopant addition rates, analyzing structural, morphological, and magnetic aspects through SEM, EDS, XRD, and VSM at different synthesis stages. The XRD pattern revealed iron, Fe(Ni), Fe(Cu), and Fe2O3 with an average crystallite size of 28–39 nm and lattice strain of 0.0097%–0.0222%. Notably, the lattice parameters decreased from 0.2852 to 0.2836 nm. Among nanocomposites, FeCu/SiO2 displayed the smallest crystallite size (34.3 nm), while FeNiSiO2 showed the highest lattice parameter (0.2853 nm). The ATR analysis unveiled Si–O–Si stretching vibrations at 1052 cm−1, intensifying with milling time. The inclusion of Cu and Ni in the FeSiO2 system significantly influenced the Si–O–Si bond. Coercivity and remanence magnetization in Fe/SiO2 increased notably with milling time, reaching 68.47 Oe and 8.73 emu g−1, respectively. The Fe/Fe2O3/SiO2 and FeSiO2 nanocomposites exhibited the maximum values of coercivity (47.07 Oe) and remanence magnetization (12.24 emu g−1). Remarkably, the Fe/SiO2 nanocomposite displayed the highest saturation magnetization, measuring an impressive 176.07 emu g−1 after 30 h of milling, while FeCu/SiO2 reached 165.64 emu g−1 after 20 h. Overall, our findings suggest the Fe/SiO2 nanocomposite as a promising high-frequency soft magnetic material.

Green synthesis of reduced graphene oxide anchored Fe3O4‐Pd hetero‐nanostructure: An efficient, magnetically separable and reusable catalyst for Beckmann rearrangement of aldoximes to amides

The multifaceted Fe3O4‐Pd@rGO nanocomposite (NC) has been synthesized successfully by a biogenic method using Ocimum tenuiflorum leaf extract. The preparation of graphene oxide (GO) was done by the well‐known modified Hummer method. The as‐synthesized Fe3O4‐Pd@rGO NC was extensively characterized by various analytical techniques, namely, Fourier transform infrared (FTIR), X‐ray diffraction (XRD), field emission scanning electron microscopy‐energy‐dispersive X‐ray spectroscopy (FESEM‐EDX), high‐resolution transmission electron microscopy (HRTEM), inductively coupled plasma‐atomic emission spectrometry (ICP‐AES), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM) and Brunauer–Emmett–Teller (BET) surface area analysis. The absence of peak corresponding to υ(CO) at 1732 cm−1 in the FTIR spectrum of Fe3O4‐Pd@rGO enumerates the reduction of GO to reduced graphene oxide (rGO) during Fe3O4‐Pd nanoparticle (NP) synthesis with O. tenuiflorum leaf extract. The XRD pattern reveals the existence of rGO, cubic‐phased spinel‐structured Fe3O4 along with the formation of metallic Pd NP without any impurities. The FESEM image designates the spherical and flake‐like morphology of the NC. The crystallite size of the NC was calculated employing the Debye–Scherrer equation and was found to be 3.45 nm corresponding to the (220) plane. The average particle size of Fe3O4‐Pd NPs as estimated from the particle size distribution curve was ascertained as 3.03 nm. The utmost saturation magnetization value of the NC as evaluated by VSM study has appeared at 0.6219 emu g−1 having coercivity value of 335.1 Oe and remanent magnetization value of 0.0767 emu g−1, suggesting the existence of a ferromagnetic material in the synthesized NC. It was a stable and highly efficient catalyst for Beckmann rearrangement of aldoximes using in an environment‐friendly medium. It afforded up to 99% isolated yield of the preferred products under acid‐free condition, avoiding the use of any harsh chemicals that will be beneficial for future industrial applications. Finally, the magnetic component of the NC allowed for easy recovery of the catalyst, thereby eliminating the chance of leaching of metal atoms, and was reusable till six successive cycles without apparent loss of its catalytic performance.

Enhanced photodegradation of CuCo2O4 nanoflower for the dye degradation of Rhodamine B and Methyl Violet

The investigation examined into the effect of different hydrothermal reaction temperatures and durations on the formation of nanoflower-shaped CuCo2O4 nanostructures (CCO NPs). The structural, morphological, functional, optical, and magnetic properties of the synthesized CCO NPs were thoroughly examined. The optimal calcination temperature was determined using Thermogravimetric and Differential Thermal Analysis (TG/DTA), which identified 400 °C as the ideal temperature. Following X-ray Diffraction (XRD) analysis, pure CuCo2O4 samples were formed, with calculated average crystallite sizes of 27 nm for CCO-A, 48 nm for CCO-B, 30 nm for CCO-C, and 31 nm for CCO-D samples. Fourier Transform Infrared (FTIR) analysis provided additional confirmation of pure CuCo2O4 formation, with characteristic bands in the 665–662 cm-1 and 583–567 cm-1 ranges indicating the presence of CuO and CoO bonds. SEM, High-Resolution SEM (HRSEM) and High-Resolution Transmission Electron Microscopy (HRTEM) all supported the observation of a distinct flower-like structural morphology. The optical properties of an optimized sample were revealed by UV–Visible Diffuse Reflectance Spectroscopy (UV-DRS) analysis, which revealed a band gap of 3.3 eV. According to Vibrating Sample Magnetometer (VSM) results, the magnetic behavior of CCO-D nanostructures at room temperature exhibited paramagnetic characteristics. The saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) values were determined to be 0.26218 emu/g, 2.7214 × 10–3 emu/g and 29.787 Oe, respectively. To evaluate photocatalytic performance, the CCO-D photocatalyst was used to degrade Methyl Violet and Rhodamine B dyes. CCO-D degraded MV dye with greater efficiency (93%) than RhB (85%) when exposed to sunlight. These findings highlight CCO-D's potential as a photocatalyst for the degradation of organic dyes.

Impact of magnetic spinel ferrite content on the structure, morphology, optical, and magneto-dielectric properties of BaTiO3 materials

Abstract In this study, the influence of magnetic content of NiFe1.93Dy0.07O4 spinel ferrite on the structural, morphological, optical, and magneto-dielectric properties of BaTiO3 materials was investigated. NiFe1.93Dy0.07O4 magnetic nanoparticles and BaTiO3 dielectric materials were firstly synthesized using the hydrothermal method and sol–gel auto-combustion route, respectively. Then, different contents of the magnetic nanoparticles were added to BaTiO3 to form a series of BaTiO3/(NiFe1.93Dy0.07O4) x samples (abbreviated as BTO/(NDFO) x ) with x = 0, 2, 5, 10, 20, and 100 %. The analysis of the structure via X-ray diffraction (XRD) technique revealed a transformation from a tetragonal structure for the pristine BTO sample to a cubic structure upon the inclusion of magnetic nanoparticles. The morphological observations and chemical composition analyses via scanning electron microscope (SEM) coupled with EDX system showed the successful formulation of biphasic products. The optical properties were investigated, and it was found that the inclusion of the magnetic phase diminishes the bandgap energy (E g ) of final BTO/(NDFO) x samples. Furthermore, vibrating sample magnetometer (VSM) was used to investigate the magnetization properties. The values of saturation magnetization (M S ) and remanent (M r ) magnetization are rising with the increase of magnetic phase content. However, the coercivity (H c ) does not show a regular variation with the increase of NDFO content. The dielectric properties were also investigated for different BaTiO3/(NiFe1.93Dy0.07O4) x samples. The obtained results showed that the real permittivity (ε′) and dielectric tangent loss (tan δ) increased with increasing temperature. Remarkably, the addition of magnetic content provokes a reduction in tan δ values compared to the pristine BTO sample. The lowest values of tan δ and highest frequency stability were noticed in the sample added with 10 % of magnetic phase. The impedance and modulus were also determined and discussed.

Modification in Magnetic Properties of CoFe2O4 Ferrite Nanoparticles Induced by 100MeV O+7 Ion Irradiation

In this work CoFe2O4 ferrite nanoparticles were prepared via sol-gel method using citric acid as chelating agent. The prepared nanoparticles was sintered at 700°C and the crystallite size is found 34 nm. In this investigation the effect of irradiation of 100 MeV O+7 beam on these nanoparticles with two fluences 5×1012 and 5×1013 ions/cm2 are studied. After irradiation the crystallite size is found to be reduced which is confirmed by transmission electron micrograph. The retentivity and coercivity changes with a measurable value while the saturation magnetization reduces slightly. The value of remanent magnetization increased from 30 emu/g to 34.6 emu/g, it can be attributed to increase of magnetic hardness. The increase in squareness ratio after irradiation leads to increase in anisotropic energy barrier of CoFe2O4 ferrite nanoparticles. Anisotropy field about doubles after irradiation and corresponding anisotropy constant also doubles with the used fluences.

Syntheses, Structural Characterization, Optical and Magnetic Properties of a New Polyoxovanadate‐Based Metal‐Organic Polyhedron

AbstractA new polyoxovanadate‐based metal‐organic polyhedron, termed V‐MOP‐19, constructed from pentanuclear {V5O9Cl} clusters and 1,4‐naphthalenedicarboxylic acid linkers, was successfully fabricated via the solvothermal method. Structural analysis revealed that V‐MOP‐19 adopts the cubic symmetry featured with an octahedral pore cage of 15.7 Å. Full characterization of V‐MOP‐19 was measured by Fourier transform infrared (FT‐IR), Raman spectroscopy, powder X‐ray diffraction (PXRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), transmission electron microscopy (TEM), thermogravimetric and differential scanning calorimetry analysis (TGA‐DSC), N2 sorption isotherm and elemental analysis (EA). The band gap energy of V‐MOP‐19, measured by UV‐Vis diffuse reflectance spectroscopy (UV‐Vis/DRS), is determined to be 2.38 eV. Moreover, the cyclic voltammetry investigation confirms a high correspondence of the band gap value (2.41 eV) with the mentioned UV‐Vis/DRS study. In particular, V‐MOP‐19 exhibits a unique magnetic property with remarkable coercivity and remanent magnetization value. These findings demonstrate that V‐MOP‐19 could be used as a potential candidate in further photocatalytic and magnetic investigations.