Saturation Magnetization Ms Research Articles

Superparamagnetic hydrophilic molecularly imprinted nanoparticles for an efficient and selective removal of tetracycline from water

In this work, a novel superparamagnetic hydrophilic molecularly imprinted nanomaterial for the removal of tetracycline (TC) was synthesized utilizing magnetite (Fe3O4) as the magnetic core, TC as the template molecule, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, and tetraethoxysilane (TEOS) as the cross-linker. Initially, Fe3O4 magnetic nanoparticles (MNP) coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. Initially, Fe3O4 MNP coated with SiO2 (MNP@SiO2) were synthesized, followed by TC molecular imprinting on the nanoparticles. The synthesis method for MNP@SiO2 was optimized, and DLS analysis of 10 replicates showed a nanoparticle size of 70.1 ± 5.8 nm, indicating high method reproducibility. The MNP@SiO2, as well as the imprinted (MNP@SiO2-MIP) and non-imprinted (MNP@SiO2–NIP) nanomaterials, were characterized by FTIR, TEM, VSM, XRD, DLS, Z potential, and BET analysis. The saturation magnetization (Ms) values were 43 emu/g for MNP@SiO2 and 32 emu/g for both MNP@SiO2-MIP and MNP@SiO2–NIP, confirming suitability for magnetic separation using external magnets. Batch binding experiments conducted in water and methanol assessed adsorption isotherms and binding kinetics, with data fitting the Langmuir isotherm model better than the Freundlich model. The developed MIP exhibited significant selectivity against other molecules with similar functional groups and size. In water, the adsorption capacity of the MNP@SiO2-MIP was 23 mg/g, with an imprinting factor of 2.2. Furthermore, the MIP demonstrated good regeneration performance. The material was tested on TC-spiked tap water samples, achieving 80.1 % TC removal with high reproducibility (3.2 %, n = 3). Combining hydrophilic superparamagnetic nanoparticles with molecular imprinting enhances their potential applications in environmental remediation, antibiotic purification, and drug delivery.

Predictive modelling of laser powder bed fusion of Fe-based nanocrystalline alloys based on experimental data using multiple linear regression analysis

This study harnessed bivariate correlational analysis, multiple linear regression analysis and tree-based regression analysis to examine the relationship between laser process parameters and the final material properties (bulk density, saturation magnetization (Ms), and coercivity (Hc)) of Fe-based nano-crystalline alloys fabricated via laser powder bed fusion (LPBF). A dataset comprising of 162 experimental data points served as the foundation for the investigation. Each data point encompassed five independent variables: laser power (P), laser scan speed (v), hatch spacing (h), layer thickness (t), and energy density (E), along with three dependent variables: bulk density, Ms, and Hc. The bivariate correlational analysis unveiled that bulk density exhibited a significant correlation with P, v, h, and E, whereas Ms and Hc displayed significant correlations exclusively with v and P, respectively. This divergence may stem from the strong influence of microstructure on magnetic properties, which can be impacted not only by the laser process parameters explored in this study but also by other factors such as oxygen levels within the build chamber. Furthermore, our statistical analysis revealed that bulk density increased with rising P, h, and E, while decreased with higher v. Regarding the magnetic properties, a high Ms was achievable through low v, while low Hc resulted from high P. It was concluded that P and v were considered as the primary laser process parameters, influencing h and t due to their control over the melt-pool size. The application of multiple linear regression analysis allowed the prediction of the bulk density by using both laser process parameters and energy density. This approach offered a valuable alternative to time-consuming and costly trial-and-error experiments, yielding a low error of less than 1 % between the mean predicted and experimental values. Although a slightly higher error of approximately 6 % was observed for Ms, a clear association was established between Ms and v, with lower v values corresponding to higher Ms values. Additionally, a further comparison was conducted between multiple linear regression and three tree-based regression models to explore the effectiveness of these approaches.

Green synthesis, characterization, and photocatalytic activity of superparamagnetic MgFe2O4@ZnAl2O4 nanocomposites

MgFe2O4@ZnAl2O4 magnetic nanocomposites were synthesized with the easy and green sol–gel method, and their photocatalytic efficiency was followed toward degradation of reactive blue 222 (RB222) dye under visible light irradiation. Prepared nanocomposites were fully characterized. The SEM and TEM images revealed the spherical morphology of the produced nanocomposites, with average size of 20–25 nm. The XRD pattern of sample exhibited the successful synthesis of the MgFe2O4@ZnAl2O4 MNCs with crystallite size 13 nm. The saturation magnetization (Ms) of the nanocomposites was examined using VSM, indicating a value of 6.59 emu/g. The absence of Hc and Mr values confirms the superparamagnetic nature of the nanoparticles. In addition, the surface area was calculated to be 78.109 m2/g utilizing BET analysis, and the band gap was determined to be 1.88 eV by DRS analysis. The photocatalytic, photolysis, and adsorption performance were investigated and result shown photodegradation activity was higher than others. These results confirm the synergetic effect between the MgFe2O4@ZnAl2O4 MNCs and visible light irradiation to degradation of organic dye. The results indicate that rapid degradation of 96% of RB222 dye occurred in just 10 min, with a TOC removal rate of approximately 59%. Furthermore, radical scavenger agents also clarified photodegradation of RB222 dye.

Multifunctional CoCe/silica and CoMnCe/silica spinel ferrite nanocomposite: in vitro and in vivo evaluation for cancer therapy

Multifunctional magnetic spinel ferrite based on CoCe and CoMnCe/silica nanocomposites (NCs) were developed for targeted cancer therapeutics. The formation of spinel ferrite and co-existence of spinel ferrite/silica/chemo-drug, surface/pore size distribution, morphological features and magnetic properties were investigated using different characterization techniques. XRD pattern confirmed the pure phase of CoCe and CoMnCe spinel ferrite with estimated crystal size of 27.9 nm. After silica coating and pegylation, the crystal size of CoCe and CoMnCe increases to 36.3 nm and 76.2 nm. Nitrogen adsorption isotherm confirm an effective embedment of both spinel ferrites into silica with large surface area (653 m2/g and 718 m2/g) and uniform pore size distributions (6.1 nm and 6.9 nm). FT-IR spectra confirm the magnetic spinel ferrite/silica interactions (977, 1705 and 3410 cm−1), cisplatin functionalization (1645 cm−1) and PEG (1275–2900 cm−1). Coating SFNPswith Si and/or Cp and/or PEG, tunes the magnetic characteristics of the NCs system. For both CoCe and CoMnCe SFNPs, saturation magnetization (Ms) of 14.96 and 10.91 emu/g, residual magnetization (Mr) of 4.40 and 2.42 emu/g, Hc (coercivity) of 1072.1 and 719.3 Oe gradually diminish upon Si, respectively. The chemical state of CoMnCe SFNPs, CoCe SFNPs, their silica and active cisplatin NCs (Pt0 and Pt2+) were investigated using X-ray Photoelectron Spectroscopy (XPS). The anti-cancer efficacy of pegylated nanoformulations were tested in in vitro cells (HeLa, HCT-116 and HEK-293) and Hemolysis assay. The toxicity of different nanoformulations administered in different concentrations (20–2000 mg/kg) in in vivo was estimated based on LD50 value.

Thermal Effects on Domain Wall Stability at Magnetic Stepped Nanowire for Nanodevices Storage.

In the future, DW memory will replace conventional storage memories with high storage capacity and fast read/write speeds. The only failure in DW memory arises from DW thermal fluctuations at pinning sites. This work examines, through calculations, the parameters that might help control DW thermal stability at the pinning sites. It is proposed to design a new scheme using a stepped area of a certain depth (d) and length (λ). The study reveals that DW thermal stability is highly dependent on the geometry of the pinning area (d and λ), magnetic properties such as saturation magnetization (Ms) and magnetic anisotropy energy (Ku), and the dimensions of the nanowires. For certain values of d and λ, DWs remain stable at temperatures over 500 K, which is beneficial for memory applications. Higher DW thermal stability is also achieved by decreasing nanowire thickness to less than 10 nm, making DW memories stable below 800 K. Finally, our results help to construct DW memory nanodevices with nanodimensions less than a 40 nm width and less than a 10 nm thickness with high DW thermal stability.

Impact of Ho substitution on structure, magnetic and electromagnetic properties hard-soft nanocomposites

This work presented the effect of Ho substitution on magnetic and electrodynamic properties of hard-soft SrBaHoxFe12-xO19@NiFe2O4 (x ≤ 0.06) nanocomposites (H/S Ho → SBFeO@NFO NCs) which were produced through one-pot citrate sol–gel method. The structure and morphology were explored using X-ray diffractometry (XRD) and scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM). By scrutinizing hysteresis curves at temperatures of 300 K (Room temperature, RT) and 10 K, the magnetic characteristics of H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs have been investigated. These materials display smooth, open hysteresis loops at both temperatures, indicating their ferrimagnetic nature and highlighting the presence of exchange-coupling interactions within the nanocomposites. The SQR (squareness ratio) values, below 0.5 at both high and low temperatures, indicate a multi-domain structure in the H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs. Magnetic parameters demonstrate fluctuations with growing Ho content. The introduction of Ho3+ ions notably reduce the coercivity of the undoped H/S Ho → SBFeO@NFO (x ≤ 0.06) NCs. Saturation magnetization (Ms) and magnetic moment show similarity between undoped and Ho-doped nanocomposites at all concentrations, except for x = 0.06, where a considerable decrease occurred at both temperatures. Our findings propose that by controlling the concentration of Ho3+ ions, the magnetic properties of H/S Ho → SBFeO@NFO NCs can be precisely adjusted. Electromagnetic properties of the H/S Ho → SBFeO@NFO NCs were investigated in the range 33–50 GHz. Frequency dispersions of the real/imaginary parts of permittivity and permeability were determined from S11 to S21 parameters. RL coefficient demonstrated intensive electromagnetic absorption with average level −16…−23 dB in this frequency range that corresponded to the absorption of the natural media.

XPS studies and ferromagnetism evaluations of pure MgO and Fe- and Co-doped MgO nanoparticles

Magnesium oxide nanoparticles (MgO-NPs), as well as Fe- and Co-doped MgO-NPs, were synthesized using a gelatin-based sol–gel method. The structure and morphology of the prepared samples were examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The results indicated that pure and doped MgO-NPs, with particle sizes below 100 nm, crystallized in cubic structures. XRD data were analyzed using the size-strain plot (SSP) method, revealing that doping increased the lattice strain to 0.11 for pure MgO, 0.18 for Co-doped, and 0.13 for Fe-doped MgO nanoparticles. The crystallite sizes were found to be 60 nm for pure MgO, 48 nm for Co-doped, and 60 nm for Fe-doped MgO nanoparticles. X-ray photoelectron spectroscopy (XPS) was used to investigate the oxidation states of the prepared samples. The Fe-doped MgO-NPs exhibited the highest value of oxygen vacancy states, indicating more defects compared to the other samples. The saturation magnetization (Ms) was measured to be 0.026 emu/g for pure MgO, 0.45 emu/g for Co-doped, and 0.62 emu/g for Fe-doped MgO nanoparticles.

Design of quaternary FeSiCoNi soft magnetic alloys towards large-power and high-frequency applications

The growing trend of large power and high frequency in electromagnetic conversion applications urges advancements in the saturation magnetization (Ms), effective permeability (μe) and core loss (Pcv) of soft magnetic composites (SMCs). Such performance depends largely on the Ms and coercivity (Hc) of the magnetic alloys as the main component of the SMCs. It is however, difficult to simultaneously achieve large Ms and low Hc via binary and ternary alloy systems. Here, quaternary Fe81-xSi15Co4Nix (x = 0, 3, 6 at%) soft magnetic alloys have been designed with the effect of Ni addition on the microstructure and magnetic properties of the alloy revealed. On one hand, rational incorporation of Co and Ni maintains the relatively large Ms. On the other hand, the Ni enters into the A2 lattice and promotes its transition into DO3 ordered phase as confirmed by both experimental characterization and first-principles calculations. Such microstructural evolution gives rise to initially decreased magnetocrystalline anisotropy (K1) followed by increasing due to the competitive reduction effect of Ni addition and increment effect of DO3 formation. The magnetostriction constants (λs) increases monotonously from negative to positive values with raised Ni content. This is accompanied with the decrease in 90° domain walls and increase in 180° domain walls as revealed by Lorentz microscopy. Combined lowest K1 and λs as well as optimized domain structure result in the lowest Hc for the Fe78Si15Co4Ni3 alloy. The corresponding SMCs exhibit excellent performance with the μe of 160.6 and the Pcv of 288.4 mW/cm3 (50 mT, 100 kHz) combined with high Ms of 177.3 emu/g, superior to other FeSi-based SMCs.

Architecting ultra-thin SiO2 shell for high magnetic performance of Fe3O4 nanoparticles for biomedical applications

This research focuses on the architectural design of the silica shell on the Fe3O4 nanoparticle to precisely control and minimize its thickness, with the aim of achieving a final product with optimal saturation magnetization (Ms) for biomedical applications. A rapid and facile microwave-assisted synthesis method was developed for the synthesis of Fe3O4@SiO2 and Fe3O4@SiO2@NH2 core–shell nanoparticles with ultra-thin SiO2 shells and excellent magnetic performance. The particle size distribution of the Fe3O4@SiO2 nanoparticles was in the range of 15–35 nm, with a mean particle size of approximately 21 nm. The mean thickness of the SiO2 shells on the Fe3O4 cores was found to be 3 nm. FTIR analysis also confirmed the successful silica coating on Fe3O4 nanoparticles and the successful amino-functionalization of silica-coated Fe3O4 nanoparticles. The Ms of Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@NH2 nanoparticles were found to be 64.4, 59.8, and 52.4 emu/g, respectively. It has been confirmed that the ultra-thin SiO2 coating has a negligible effect on the magnetic characteristics of the nanoparticles. The developed microwave-assisted synthesis method in this study not only provides an interesting, rapid, and facile synthesis route but also results in a product with a narrow particle size distribution, an ultra-thin SiO2 shell, favorable magnetic properties, and improved cell compatibility, which may be used in several different applications, particularly biomedical applications.

Magnetic and magnetostrictive properties of Cu-doped cobalt ferrite

The Cu-doped cobalt ferrites CuxCo1-xFe2O4 (CCFO) were synthesized by a glycine-nitrate sol-gel auto-combustion method and investigated for structural, magnetic and magnetostrictive properties. X-ray diffraction and scanning electron microscopy analysis revealed the formation of single cubic-spinel phase for all the as-prepared powders, followed by the sintered samples with grain sizes around 2.5 µm. The variation in stoichiometric composition can be used to tailor magnetic and magnetostrictive properties. Saturation magnetization MS decreases from 84.8 to 60.4 emu/g with increasing Cu content from x = 0.0 to x = 0.50, accompanied with a reduction in coercivity HC from 1.21 to 0.41 kOe. The introduction Cu into CFO is conductive to the decline in magnetocrystalline anisotropy, giving rise to an improvement in magnetostriction at low applied fields. An optimized composition in the CuxCo1-xFe2O4 ferrites is found to be around x = 0.30, achieving good magnetoelastic properties, i.e., a large saturation magnetostriction (–λS ∼ 240 ppm), a high strain sensitivity (–dλ/dH ∼ 1.44 nm/A), as well as a low magnetocrystalline anisotropy coefficient (K1 ∼ 3.7 × 106 erg/cm3). The excellent magnetoelastic properties and the combination in a facile synthesis process for sintered polycrystalline ferrites, suggest promising prospects in magnetostriction applications.

Lanthanum Substituted Mg-Zn Ferrite Nanostructures: A Comprehensive Study of Cation Distribution, Structural, Morphological, Optical, Magnetic, Dielectric, and Electromagnetic Traits

The sol-gel auto-combustion (SC) procedure was utilised to fabricate lanthanum-doped Mg-Zn nanostructures with the chemical composition, Mg0.6Zn0.4LaxFe2-xO4, (x = 0, 0.05, 0.10). X-ray diffraction showed nanocrystalline and single-phase of Mg-Zn nanostructures. The morphological traits showed formation of irregular and aggregated grains. Fourier transform infrared spectroscopy detected the formation of two characteristic band positions that fall within the range of 400 to 600 cm−1 and may occur because of stretching vibration within metal-oxygen (M-O) cations located at interstitial positions. From the M-H loops, the excellent values of magnetic factors, such as the saturation magnetization (Ms), rentivity (Mr), and coercivity (Hc) ranging from 35.30 to 44.79 emu g−1, 1.40 to 3.75 emu g−1, and 11.56 to 41.42 Oe were obtained. The loss tangent (tan δ) was observed to be miniscule for all of the samples due to which they can be useful for electronic applications. However, the initial values of the real permeability ( μ′ ) was high and it decreases until 4 GHz, after which it acquires a constant value for rest of frequency range. However, observed low values of the magnetic loss tangent (tan δ μ ) were due to the large grain size and the high densification of the samples.

The role of Cr in optimizing properties of Fe–B–C–P–Si–Mo–Cr metallic glasses for applications

With the rapid development of third-generation semiconductors, there is an urgent need to develop high-performance soft magnetic Fe-based metallic glasses tailored particularly for their high-frequency applications. In this work, new Fe76−yB7C7P7Si3Moy−xCrx (y = 0, 1, 2, 3 at.%, x ≤ y) alloys with relatively high glass-forming ability (GFA) were developed. The effects of replacing Mo with Cr on GFA, thermodynamic properties, soft magnetic properties, electrical resistivity (ρ), and corrosion resistance at different Fe contents were systematically studied. The possible causes of GFA variation were discussed. The results show that the addition of a small amount of Cr replacing Mo under different Fe contents would not lead to a decrease in GFA. The critical sizes of Cr-containing glassy alloys are 1–2.5 mm. These alloys possess relatively high saturation magnetization (Ms) of 1.29–1.41 T and lower coercivity (Hc) of 0.7–1.8 A/m, contributing to the reduction of hysteresis loss. In addition, Cr increases ρ of the alloys, reaching up to 162 μΩ cm, which is beneficial to reducing eddy current loss at high frequency. Furthermore, Cr effectively enhances corrosion resistance, thereby increasing the service life of the alloys in harsh environments. The role of Cr in these aspects makes it a beneficial element in soft magnetic metallic glasses for high-frequency applications.

Effect of Cd on Structural, Spectral, Morphological and Dielectric Properties of Sr1-xCdxZn2Fe4O11 R-type Hexaferrites Synthesized via Sol-gel Technique

Sol–gel method was used to prepare Sr1-xCdxZn2Fe4O11 (x = 0.00, 0.02, 0.06, 0.1) R-type hexaferrite. The synthesized materials were sintered at 850oC and desired phase was obtained. X-ray diffraction analysis confirms that R-type hexaferrite exists only as a single phase. Using the Scherer formula, crystallite size for all of the prepared samples was found to be in the range of 10.39–12.62 nm. Crystallite size (D), the lattice parameters (a, c), and the cell volume (Vcell), d-spacing, bulk density, X-ray density, porosity, dislocation density and micro strain were determined in structural analysis. Fourier transform infrared spectroscopy method was used to identify the metal-oxygen vibrations at different locations. FT-IR verifies the presence of the Fe–O stretching vibration band at 743 and 867 cm−1. The typical grain size in surface morphology investigation ranges from 0.56 to 0.82 μm. Dielectric response of ferrite ceramic samples replaced with Cd2+ was investigated in the frequency range of 1 MHz–3 GHz. The AC conductivity rises with an increase in frequency because they are proportional to one another. This increasing tendency is effectively described by the theory of Maxwell-Wagner and Koop. Q-values remain constant as frequency rises and behaves independently of frequency as long as frequency reaches 1.7 GHz. These types of materials are utilized in high-frequency applications including frequency filters and resonant circuits. All of the magnetic properties determined by analyzing the M − H loops, including saturation magnetization (Ms), retentivity (Mr), and coercivity (Hc), exhibit an increasing trend as the substitution of Cd2+ rises. Ms (49.76–56.38 emu/g), Mr (15.82–18.30 emu/g) and Hc range from 203.20 Oe to 215.80 Oe. Grain size decreases cause arise in coercivity, which is caused by an enhancement in magneto-crystalline anisotropy. Overall results suggest that Cd2+ replaced R-type hexagonal ferrites are a great resource for longitudinal recording media; they have the potential to be used in a wide variety of electronic applications, including resonant circuits and high-frequency filters, security, detecting and switching.

Stabilizing magnetic order of cobalt-based anisotropic nanoparticles prepared using NaBH4 as a reducing agent

A one-pot chemical method was used to prepare cobalt nanoparticles (Co NPs) by employing sodium borohydride (NaBH4) as a reducing agent, as well as graphite and activated carbon as stabilizer materials. The resulting NPs were characterized by XRD, FE-SEM, EDX mapping and VSM measurements before and after annealing under a mixture of argon and hydrogen atmosphere at 600 ℃, in order to study their structural, morphological, and magnetic properties. This study focused on the shape and size of Co NPs, involving the formation of Co and Co3O4 phases with the effect of oxygen as the main factor that can significantly contribute to the magnetic anisotropy. Co NPs exhibited a high saturation magnetization (Ms) value after performing the annealing process, achieving Ms> 99 emu/g when using the graphite stabilizer. The results indicate that surface atoms play a significant role in the modification of magnetic characteristics of Co NPs.

Effects of La-Co Co-Substitution and Magnetic Field Pressing on the Structural and Magnetic Properties of SrM Hexaferrites

We carefully investigated the effects of La-Co co-substitution and magnetic field pressing (MFP) on the structural and magnetic properties of SrM hexaferrites. Samples composed of Sr1−xLaxFe12−xCoxO19 were sintered at 1230 °C for 2 h in air with sintering additives composed of 0.7 wt% CaCO3 and 0.7 wt% SiO2. A single M-type phase was confirmed to exist up to x = 0.3. Rietveld refinement revealed a slight decrease in lattice parameter a and the unit cell volume (Vcell) with an increasing x, while parameter c showed a significant decrease. The saturation magnetization (Ms) values increased from 70.90 to 72.40 emu/g with an increasing x from 0.0 to 0.15 and then decreased to 71.38 emu/g with further increasing of x to 0.3, while the anisotropy field (Ha) increased from 17.7 to 25.9 kOe, leading to a continuous increase in the intrinsic coercivity (Hci), from 3.52 to 5.00 kOe, respectively. Using the MFP process, the c-axis of M-type hexaferrite grains could be effectively aligned to the applied field direction, which significantly affected the microstructures and, thus, magnetic properties of samples. Unlike non-MFP samples, exhibiting a significant increase in the average grain size (davg) but almost unaltered average thickness (tavg) with an increasing x from 0.0 to 0.3, MFP-processed samples exhibited almost unaltered davg values but a continuous decrease in tavg. Consequently, the variation in remanent flux density (Br) versus x followed that of Ms versus x and thus exhibited the highest Br of 4.05 kG for x = 0.15, leading to the highest maximum energy product {(BH)max} of 3.62 MGOe. With an increasing x from 0.0 to 0.3, the Hci values continuously increased from 3.14 to 3.84 kOe mainly due to a continuous increase in Ha, although they were significantly lowered in comparison with those of non-MFP samples because of a large increase in Br for a given composition x. A higher Mr/Ms ratio always resulted in a larger (BH)max in our samples regardless of x. A careful comparison of the microstructures and magnetic properties between MFP and non-MFP samples provided valuable insights into a broad area of permanent magnet optimization.

Enhanced Hard Magnetic Performance for MnBi Green Powders

Mn55Bi45 melt - spun ribbons were prepared by using the melt-spinning technique followed by annealing in Ar/5%H2 gas mixture. The in-situ formation of ferromagnetic phase (denoted as LTP) of MnBi was observed by the multi-section cycled Differential Scanning Calorimetry (DSC) method. It was found that, the optimal annealing temperature range for forming MnBi LTP is 250 – 280 oC. The prolonging annealing time increases the content of MnBi LTP leading to the increase of saturation magnetization Ms but paid by the drop of the intrinsic coercivity iHc. The MnBi green powders were prepared by the Low Energy Ball Milling method (LEBM) in N2 liquid. The maximum energy product of MnBi green powders is estimated about 10.8 MGOe.

High photocatalytic degradation of methylene blue and enhancing the magnetization, AC conductivity of Dy3+ and Ce3+ doped CdCoFe2O4 nano ferrites

Photocatalysts that combine with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. A series of Cd0.4Co0.6DyXCeXFe2-2XO4 spinel nano ferrites (nFs) were synthesized by using a highly efficient low-temperature method of citrate sol-gel auto-combustion for Methylene Blue (MB) dye degradation photocatalysts under visible light irradiation that combines with dielectric and magnetic properties are vital because of a wide variety of applications for these combinations, and nanostructured magnetic semiconductive materials have attracted significant interest due to their potential applications. The recycled MB is one of the hazardous textile dyes that is used extensively but causes risks for both humans and the environment. The prepared Dy3+ and Ce3+ doped Cd–Co nFs were polycrystalline with cubic structure, and crystalline size was increased from 15.78 to 21.02 nm with higher crystallinity, and the surface morphology changes from a spherical shape to a hexagonal shape with higher doping concentrations. The direct optical band gap values are increased. FTIR spectra reveal the stretching vibrations along the [M↔O] bond tetrahedral (A) and octahedral (B) sites. HRTEM results revealed that the prepared Cd–Co nFs have higher crystalline nature and high porosity. VSM indicates the sample's soft magnetic action and hysteresis loops showed the highest saturation magnetization (Ms) is 12.243 emu/g, and retentivity increases around 6.038 emu/g, decreasing the dielectric tangent loss, dielectric constant and dielectric loss. The AC conductivity raised with applied frequency. The PL gives a blue emission, and photocatalytic has the highest degradation activity 40.93 % of MB would be successful after 120 min irradiation of X = 0.07 Dy3+ and Ce3+ doped Cd–Co nFs.

Effect of Annealing Temperature on the Characterizations of Cobalt Ferrite Nanoparticles Synthesized via Co-precipitation

This study investigates the effect of annealing temperature on the structural and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles synthesized via the co-precipitation method. The results indicate that the annealing temperature significantly enhances the crystal size and quality, yielding well-defined, impurity-free CoFe2O4 crystals. Magnetic measurements reveal that both saturation magnetization (Ms) and coercivity (Hc) are improved with annealing. The nanoparticles exhibit a soft-magnetic, single-domain state up to an annealing temperature of 1200°C. They reach a critical size of 39.7 nm and begin transitioning to a multi-domain state. These findings highlight the crucial role of annealing temperature in optimizing the properties of CoFe2O4 nanoparticles for potential applications in magnetic recording media, magnetic resonance imaging, magnetic fluid hyperthermia, biosensors, drug delivery, and cell separation.

Hydrogen-annealing modulated magnetocaloric effect and critical behavior of Weyl semimetallic Co3Sn2S2

Modulating the electron interaction and magnetic domains is an essential strategy to evoke novel physical properties, both for fundamental research and for related magnetic applications. The emerging annealing process attracted attention due to its capability of tuning the magnetic performance, but it has been rarely studied. Herein, we conducted hydrogen annealing on the Weyl semimetallic Co3Sn2S2 and investigated the magnetic interaction, critical behavior, and magnetocaloric effect (MCE). Hydrogen-annealed Co3Sn2S2 (HA-Co3Sn2S2) exhibits a distinct anisotropy-dependent magnetic behavior, where a typical second-order transition with an easy magnetization process is observed under H//c. However, a frustrated magnetic state composed of ferromagnetic (FM), antiferromagnetic (AFM), and/or spin glass phases is observed when H//ab. Critical analyses illustrate that the ground state of HA-Co3Sn2S2 lies between the 3D-Ising model and the Mean-filed model, indicating the presence of both long-range and short-range magnetic interactions in the system. Additionally, we found that HA-Co3Sn2S2 exhibits an enhanced saturation magnetization (Ms) and magnetic refrigeration capacity, both showing anisotropic dependence, compared to the pristine Co3Sn2S2. Our work develops hydrogen annealing to modulate electron coupling and magnetic domains, paving the way for further studies of anisotropic magnetic behavior and applications in magnetic refrigeration.

Optimization of the coating process in the PEGylated chitosan-based doped cobalt ferrite nanoparticles for hyperthermia applications using the Taguchi method

In this study, the parameters of coating process in the PEGylated chitosan-based doped cobalt ferrite nanoparticles for hyperthermia applications was optimized using the Taguchi method. The effect of chitosan and polyethylene glycol as well as the glutaraldehyde (crosslinker) contents on the structural, microstructural, and magnetic properties and the colloidal stability of the nanoparticles were investigated. Ultimately, to optimize the properties of the nanoparticles, the Taguchi method (L16 orthogonal array) was employed. The incorporation of the Ca2+ and Gd3+ into the spinel structure with an average crystallite size of 21 nm was successfully verified by X-ray diffraction (XRD) and the Rietveld refinement analysis. Moreover, thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy (FT-IR) demonstrated the effective functionalization of the chitosan and polyethylene glycol coatings. Vibrating sample magnetometer (VSM) measurements revealed that saturation magnetization (Ms) was achieved in the range of 54.91–60.42 emu/g. Also, microstructural observations indicated that the coating layer can affect the particle size distribution and morphology. The Taguchi method identified that the glutaraldehyde content is the most expressive parameter influencing the nanoparticles’ properties, with the optimum properties achieved at chitosan, polyethylene glycol, and glutaraldehyde of 0.4 g, 0.08 g, and 1.2 ml, respectively. The antibacterial analysis confirmed the promising potential of the coated nanoparticles for biomedical applications. Furthermore, the magnetic heating efficiency of the synthesized nanoparticles was investigated in various concentrations of magnetic fluid, demonstrating their suitability for magnetic hyperthermia application.