Saturation Magnetization Value Research Articles

Structural design of La2(CO3)3 loaded magnetic biochar for selective removal of phosphorus from wastewater

High levels of phosphorus released into the environment can cause eutrophication issues in wastewater, therefore discharge concentrations of such element are regulated in many countries. This study addresses the pressing need for effective phosphorus removal methods by developing a novel La2(CO3)3 and MnFe2O4 loaded biochar composite (LMB). A remarkable adsorption capacity towards the three forms of phosphorus from wastewater, including phosphate, phosphite, and etidronic acid monohydrate (as a representative of organic phosphorus), was exhibited by LMB (88.20, 16.35, and 15.95 mg g−1, respectively). The high saturation magnetization value (50.17 emu g−1) highlighted the easy separability and recyclability of the adsorbent. The adsorption process was well described by the Langmuir isotherm model and the pseudo-second-order kinetic model, which mainly involved chemisorption. Characterization results confirm the effective loading of La2(CO3)3 with ligand exchange and electrostatic attraction identified as the primary mechanisms. Importantly, the LMB demonstrated exceptional selectivity for phosphorus in wastewater samples containing various substances, exhibiting minimal interference from competing ions (Cl−, NO3−, SO42−, and CO32−). These findings enhance the understanding of LMB's application in efficient wastewater phosphorus removal. Holding significant promise in wastewater remediation, the LMB acts as an effective adsorbent, contributing substantially to the prevention and control of various types of phosphorus pollutants, thereby mitigating wastewater eutrophication.

Parameters adjustments for facile synthesis of high magnetization iron oxide nanoparticles from natural sand

This study explores the synthesis of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) by leveraging natural iron sand and steel wool as primary raw materials within the co-precipitation method, which reduces the cost of production compared to the commercial counterparts. The research systematically investigated the influence of the diethylamine percentage, annealing time and annealing temperature on the SPIONs’ synthesis from natural iron sand by the co-precipitation method. Fe3O4 with varying crystallite sizes, ranging from 11.5 to 14.7 nm, were confirmed. SEM highlighted the nanoparticle agglomeration, a concern addressable through surface modification techniques, as further emphasized by TEM, which confirmed the nano-scale dimensions. Magnetic saturation values were confirmed by VSM, ranging from 37 to 51 emu/g. These values established the superparamagnetic behavior, rendering the nanoparticles suitable for versatile applications. The study identifies a potential threshold effect of the diethylamine concentration on the magnetic saturation and suggests an optimum annealing temperature for energy efficiency. This research contributes valuable insights into harnessing natural iron sand for SPION synthesis, advancing cost-effective and sustainable approaches in nanomaterial development, while emphasizing the importance of parameter customization for producing high-quality SPIONs.

Effect of Ag-doping process into the yttrium iron garnet (Y3Fe5O12) thin films on the structural, magnetic and optical properties

In this work, the effect of Ag doping process (directly and as a nanoparticle) into the Y3Fe5O12 (YIG) thin films on the structural, morphological, optical and magnetic properties was studied in detail. Ag-doped YIG thin films were grown on thermally oxidized Si substrates by following sol–gel and spin-coating methods. All films were crystallized without cracks by two-stages heat treatment process. The XRD patterns confirm the formation of YIG peaks, and metallic Ag peaks which settled into the structure without bonding with the YIG components. In both Ag doping processes, the coercive field (Hc) and saturation magnetization (Ms) values of the samples containing 3% Ag are significantly lower than the other samples. The Ms values of 5% Ag doped samples were found the highest in both series. The Ms values of the films between in-plane and out-of-plane measurement increased with the Ag concentration. The optical measurements indicate an absorption peak in the range of 0–4 eV in both sample series and the optical band gap of the films decreased with the Ag doping due to its metallic characteristic. The ferromagnetic resonance measurements indicate that the lowest FMR linewidth as 92 Oe is seen in the 1% Ag-doped YIG sample. The relatively cheap and easy production of the used method and additive material may enable the widespread the usage of Ag-doped YIG thin films in magneto-optical devices.

SYNTHESIS AND CHARACTERIZATION OF MAGNETITE FE3O4 NANOPARTICLES FROM NATURAL IRON SAND in GELAR RIVER

Fe3O4 nanoparticles made from the natural iron sands of the Gelar River have been successfully synthesized using the coprecipitation method. Test the content of Fe elements in pure iron sand and characterize them using XRF after separation. Fe3O4 nanoparticle characterization uses XRD to determine the sample's lattice parameters and crystal size. The nanoparticles' morphology, structure, particle shape, and elemental content were characterized using SEM-E DX. Magnetic properties and magnetic saturation values are characterized using VSM. XRF yield on iron sand before separation contains Fe 59.46%. After separation, the Fe content rose to 84.72%. The synthesis results obtained brownish-black Fe3O4 nanoparticle powder that permanent magnets can attract. Based on the XRD results, the crystal structure formed is cubic inverse spinel with crystal lattice Å with a particle size of 14.8 nm. The SEM-EDX results show the morphology of spherical nanoparticles with multiple agglomerations. Particle size is 40 nm. The EDX spectrum confirmed the formation of Fe3O4 nanoparticles in the presence of Fe (51.79%) and O (25.68%). The VSM results show that Fe3O4 samples have ferromagnetic properties with saturation magnetization (MS) = 27.36 emu/g, remanent magnetization (Mr) = -0.01 emu/g, and coercivity field (Hc) = 0.01 T.

Sustainable Industrial Wastewater Treatment and Antibacterial Activity using Environmental Friendly Ferrite Nanoparticles

A comparison studies of two unique bimetallic spinel ferrite nanoparticles synthesized by the sol-gel process, namely Co-NiFe2O4 andCu-ZnFe2O4 were investigated. Various characterization approaches were utilized to examine the structural, morphological, magnetic and electrical characteristics of the nanoparticles. Both Co-NiFe2O4 and Cu-ZnFe2O4 nanoparticles formed single-phase spinel structures, according to X-ray diffraction (XRD) research whereas FTIR spectra provided information about the vibrational modes and chemical bonding within the nanoparticles confirmed the presence of desired metal-oxygen bonds chemical bonding within the nanoparticles. The UV-Vis spectroscopy revealed the optical absorption properties of the nanoparticles indicating the presence of energy bandgaps in the visible range. Scanning electron microscopy (SEM) images suggested the uniform and well-dispersed nanoparticles with average sizes in the nanoscale range. Vibrating sample magnetometry (VSM) measurements demonstrated that both Co-NiFe2O4 and Cu-ZnFe2O4 nanoparticles exhibited ferromagnetic behaviour at room temperature. The saturation magnetization values were found to be higher for Co-NiFe2O4 nanoparticles compared to Cu-ZnFe2O4 nanoparticles, suggesting the superior magnetic properties of the former. As a result, ferrites demonstrate promise in industrial wastewater treatment, facilitating efficient heavy metal removal and advanced organic pollutant degradation, contributing to a sustainable and effective solution. The antibacterial efficacy of synthesized bimetallic ferrite nanoparticles against Salmonell typhi, Escherichia coli, Staphyloccus aureus, Bacillus cereus proves that the synthesized ferrite nanoparticles possess a good antibacterial activity against the selected pathogens.

The influence of electrodeposition potential on the chemical composition, structure and magnetic properties of FeCoNi nanowires

FeCoNi alloyed nanowires with diameters of 40 nm and 100 nm and a length of 6 µm were electrodeposited in the polycarbonate membranes at constant cathodic potentials ranging from −1.0 to −1.8 V. The increase in cathodic potential caused an increase in Ni content with a simultaneous decrease in Fe and Co concentrations. The samples showed an fcc structure (with a small hcp fraction observed in one sample) with a preferred growth along [111] direction, which changed to a [220] texture at higher deposition potentials. With the increase in Ni content, a shortening of the lattice parameters and an increase in the crystallite size were observed. Various chemical compositions resulted in the modification of the magnetic properties of nanowires. The magnetization saturation value increased with increasing cathodic potential for both types of nanowires. However, coercivity and squareness rose for samples with a diameter of 40 nm and fell down for 100 nm diameter nanowires. This specific behavior was explained based on dipolar interactions, which can be neglected in 40 nm diameter nanowires, due to the low membrane porosity.

Structural, thermal, magnetic and microwave-absorbing properties of spinel-structured high entropy oxide (MnFeCoNiX)3O4 (X = Zn, Cu, Cr)

Within the present work, a series of spinel-structured (MnFeCoNiX)3O4 (X = Zn, Cu, Cr) high entropy oxides (HEOs) were fabricated by co-precipitation method and the subsequent heat treatment. The phase composition, microstructure, thermal stability, magnetic property and electromagnetic (EM) wave loss ability were comprehensively studied. It is found that spinel-structural (MnFeCoNiX)3O4 HEOs are well-crystallized at above 800 °C with a space group Fd-3m. Morphological analysis reveals that grains of different HEOs contain nano-domains with particle sizes between 100 nm and 500 nm. In addition, Mn, Ni, Co, Fe, Zn, Cr and Cu elements are homogeneously distributed and the chemical states of Mn, Ni, Co and Fe are all +2 and + 3, while Cu only exists in +2 state. Thermal stability analysis shows that (MnFeCoNiCu)3O4 HEO is able to keep stable at 1000 °C. Moreover, the (MnFeCoNiCu)3O4 sample exhibits the best magnetic properties and EM microwave loss ability in comparison with (MnFeCoNiZn)3O4 and (MnFeCoNiCr)3O4. For (MnFeCoNiCu)3O4, the values of saturation magnetization (Ms) and coercivity (Hc) are 38.6 emu/g and 52.6 Oe, respectively. Meanwhile, (MnFeCoNiCu)3O4 displays a minimum reflection loss (RL) of −15.5 dB at 8.48 GHz with a thickness of 4.5 mm and a wide effective absorption bandwidth (EAB) of 8.84 GHz with the sample thickness of 5 mm. It is expected that the excellent high-temperature stability and good EM wave absorbing performance of high entropy (MnFeCoNiCu)3O4 could make it potentially useful in EM wave absorption under elevated temperatures.

Designing bi-functional Ag-CoGd0.025Er0.05Fe1.925O4 nanoarchitecture via green method

In the current study, we developed a simple and biocompatible method for producing core–shell nanoparticles (NPs). Citrate auto combustion and green procedures were used to create core–shell Ag/CoGd0.025Er0.05Fe1.925O4 (Ag/CGEFO) sample with an average crystallite size of 26.84 nm. The prepared samples were characterized via different structural techniques, such as x-ray diffraction (XRD), Raman Spectroscopy (RS), High-Resolution Transmission Electron Microscopy, and Energy Dispersive x-ray analysis. These analyses were utilized to characterize and confirm the successful formation of the core–shell architecture. For core–shell NPs, all peaks of Ag and CGEFO ferrite are detected in the XRD, confirming the co-presence of the ferrite spinel phase and the cubic Ag phase. The magnetic hysteresis curves demonstrate typical hard ferri-magnetic behavior along with maximum magnetic saturation values up to 53.74 emu g−1 for the CGEFO sample, while an enhanced coercivity is detected for the coated sample. Moreover, the width of the hysteresis loop is increased for the Ag/CGEFO sample compared to the uncoated one. This indicates that the addition of Ag as a shell increases magneto crystalline anisotropy. Moreover, the E g of uncoated CGEFO is equal to 1.4 eV, increasing to 3.6 eV for coated ones. This implies the influence of CGEFO is diminished when the surface is coated with Ag (shell), and the reflectance of the Ag/CGEFO core–shell is nearly dependent on the reflectance of the Ag shell layer. Consequently, the Ag/CGEFO can be used as a light shielding substance.

Bifunctional of Fe3O4@chitosan nanocomposite as a clarifying agent and cationic flocculant on different sugar solutions as a comprehensive semi industrial application

In the sugar industry, eliminating side impurities throughout the manufacturing process is the most significant obstacle to clarifying sugar solutions. Herein, magnetic chitosan (MCS) nanocomposite was Fabricated to be used as a biodegradable, environmentally friendly clarifying agent throughout the cane juice and sugar refining processes. Fe3O4 was synthesized using the coprecipitation procedure, and then MCS was combined using a cross-linking agent. Furthermore, 14.76 emu g−1 was the maximum saturation magnetization (Ms) value. Because MCS is magnetically saturated, it may be possible to employ an external magnetic field to separate the contaminant deposited on its surface. Additionally, zeta potential analysis showed outstanding findings for MCS with a maximum value of (+) 20.7 mV, with improvement in color removal % up to 44.8% using MCS with more than 24% in color removal % compared to the traditional clarification process. Moreover, utilizing MCS reduced turbidity from 167 to 1 IU. Overall, we determined that MCS nanocomposite exhibits considerable effectiveness in the clarifying process for different sugar solutions, performing as an eco-friendly bio-sorbent and flocculating material.

Investigation of gadolinium doped manganese nano spinel ferrites via magnetic hypothermia therapy effect towards MCF-7 breast cancer

Magnetic spinel ferrite nanoparticles (MSF-NPs) are potential candidates for biomedical applications, especially in cancer diagnosis and therapy due to their excellent physiochemical and magnetic properties. In the current study, MSF-NPs were fabricated by sol-gel auto combustion method. The crystal structure and surface morphology were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The magnetic properties were studied by VSM (vibrating sample magnetometer). As increasing Gd3+ concentration, the saturation magnetization values decreased from (17.8-2.3) emu/g, while the coercivity decreased from (499-133) Oe at room temperature. Finally, the fabricated MSF-NPs were tested against anticancer activity by MTT assay. The IC50 = 21.27 μg/mL value was observed, showing the strong antiproliferative activity of these nanoparticles. These results suggested that the obtained MSF-NPs would be useful for remote-controlled hyperthermia therapy for cancer treatment and MRI application due to their excellent magnetic properties. These distinct properties make MSF-NPs most suitable for cancer treatment and bright Contrast Agents (T1-MRI).

5-Fluorouracil-loaded designed manganese-dysprosium sulfide composite nanoparticles and their in vitro cancer cell inhibition

Sulfide nanoparticles are an intriguing class of nanomaterials, employed in various biomedical applications including cancer diagnosis and treatment. The current study explores the multifaceted characteristics and potential applications of poly-β-cyclodextrin (poly-CD)-coated manganese-dysprosium-sulfide (Mn-Dy-sulfide) and manganese sulfide nanoparticles. The Mn-Dy-sulfide nanoparticles exhibit an average crystallite size of 21.97 nm, signifying their nanoscale nature. In terms of magnetic properties, these nanoparticles demonstrate weak saturation magnetization values and positive magnetic susceptibility, with a notable MS of 0.6019 emu/g and a coercivity value of 277.95 Oe for the poly-CD coated Mn-Dy-sulfide nanoparticles. Moreover, these nanoparticles serve as effective drug carriers, with drug loading contents of 7.35 % and an impressive drug encapsulation efficiency of 77.93 %. Their drug release profile reveals approximately 50 % drug release at around 110 h (pH 7.4) and 160 h (pH 6.0), offering controlled drug delivery capabilities. Crucially, the anticancer activity of these nanoparticles is evident in their IC50 values. Mn-Dy-sulfide nanoparticles loaded with 5-fluorouracil exhibit a low half-maximal inhibitory concentration (IC50) of 7.9 ± 0.5 μg mL−1, demonstrating their potential as effective anticancer agents. Precisely, these poly-CD coated Mn-Dy-sulfide nanoparticles exhibit exceptional characteristics, including nanoscale size, high crystallinity, magnetic responsiveness, optical properties, drug delivery capabilities, and potent anticancer activity.

Investigations of Crystal Structure and Magnetic Properties of Mn<sub>0.3</sub>Fe<sub>2.7</sub>O<sub>4</sub>/PEO/PMMA/AC Nanocomposites

The Mn0.3Fe2.7O4/PEO/PMMA/AC nanocomposites were synthesized using co-precipitation and solid-state reaction methods. The Mn0.3Fe2.7O4/PEO/PMMA/AC nanocomposites were success formed. This was confirmed by characterization using FTIR instrument. The Fe-O, C-O, and C-H2 functional groups were the representation of Mn0.3Fe2.7O4, PEO/PMMA, and AC respectively. Investigation of crystal structure was characterized using XRD instrument. According to X-Ray Diffraction analysis, the crystal size was 10.82 nanometers and the peak of AC was detected on 2θ around 24.85o. In addition, the investigation of magnetic properties was characterized using VSM instrument. This result showed that the Mn0.3Fe2.7O4/PEO/PMMA/AC nanocomposites behave as a superparamagnetic material with a saturation magnetization value was around 12.55 emu/gram.

Preparation and resistive switching properties of ZrO2 films with large room-temperature ferromagnetism

In this study, ordered porous ZrO2 films were prepared on porous Al2O3 films by magnetron sputtering. The films showed large room-temperature ferromagnetism, and it was also observed that the porous ZrO2 films have magnetic anisotropy. The magnetism in the direction perpendicular to the film surface was much greater than in the direction parallel to the film surface. A saturation magnetization value which was up to 3.19 × 10−4 emu was obtained for the ZrO2 film with pores of 42.55 nm in diameter when the external field was perpendicular to the film surface. The saturation magnetization strength per unit volume is 509.26 emu/cm3. After a photoluminescence (PL) spectrum and X-ray photoelectron spectroscopy (XPS) test on the film, it was found that oxygen vacancy content has a direct effect on the film’s magnetism. In addition, some Ag/ZrO2/PAA/Al devices were prepared, and the resistive switching properties of the ZrO2 films were tested. The research in this paper provides ideas for the development of spintronic devices.

A comparative investigation of structural, magnetic and photocatalytic properties of pure, Ce-Ni and Cd-Ni co-doped BiFeO3 nanoparticles

Bismuth ferrite, BiFeO3 (BFO) as well as Ce-Ni, Cd-Ni co-substituted BiFeO3 nanoparticles were prepared using the sol–gel route. XRD and Raman results show a structural phase transformation from rhombohedral (pristine BFO) to orthorhombic in the case of Bi0.94Cd0.06Fe0.94Ni0.06O3 (BCdFNO6), which implies that Cd substitution can induce the obvious transition of crystal structure while Ce substitution Bi0.94Ce0.06Fe0.94Ni0.06O3 (BCeFNO6) cannot. An apparent blue shift can be noted in all the substituted samples and with a reduction of the direct optical bandgap compared with the pristine BFO. The XPS findings show that Ce-Ni and Cd-Ni substitution increases the Fe3+ ions (Cd-Ni co-doped samples reveal the best outcomes), which would be evidence for reducing oxygen vacancies and improving magnetism. Cd-Ni co-substituted into BFO can improve magnetic properties because the ionic radii of Cd2+ ion are smaller than that of Bi3+ ion; moreover, intriguingly, the room temperature magnetic (M−H) hysteresis loops reveal the greatest saturation magnetization value in Cd-Ni co-substituted samples. The co-doped of Cd-Ni, has the greatest degradation activity 99.48 % of MB and 98.76 % of RhB would be successes after 90 min irradiation, which was raised by 9.49 %, 25 % of MB and 9.52 %, 26.92 % of RhB from that of the Ce-Ni co-doped and pristine BFO.

Anionic magnetic nanosorbents immobilized with peptide aptamer for selective adsorption with bisphenol A

This study focused on synthesis of anionic magnetite nanoparticles (MNPs) immobilized with a bisphenol A (BPA)-specific peptide aptamer for selective BPA adsorption. The MNP surface was coated with anionic poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) to provide water dispersibility and stability. These nanosorbents, with a saturation magnetization value of 47 emu/g, responded well to the change in zeta potential and hydrodynamic size with varying dispersion pH. The aptamer loading capacity of particles was 0.12 mg/mg MNPs, and the nanosorbents exhibited a 47% BPA adsorption capacity. Importantly, they shown high selectivity in capturing BPA over structurally similar molecules.

R-GO coated magnetic high entropy alloy/oxide nanocomposites as highly efficient Fenton and photo-Fenton catalysts

To utilize the synergistic effect of high entropy alloy, high entropy oxide and r-GO (reduced graphene oxide), we prepared r-GO coated nanocomposites comprising bcc high entropy alloy/spinel high entropy oxide (H730) and bcc high entropy alloy/hexagonal high entropy oxide (H725), encompassing elemental constituents such as Aluminum (Al), Chromium (Cr), Manganese (Mn), Iron (Fe), and Cobalt (Co). The samples were meticulously synthesized using the sol-gel technique followed by subsequent calcination at a temperature of 700 °C under nitrogen or air atmospheres. The assessment through X-ray diffraction and electron diffraction methodologies conclusively confirmed the successful formation of nanocomposite structures. The electron microscopy and Raman spectroscopy confirmed the r-GO coating over both the composites. The saturation magnetization values of 32 and 10 emu/g were noticed at 30 kOe for H730 and H725 samples, respectively. In-depth analysis using X-ray photoelectron spectroscopy revealed the coexistence of diverse oxidation states within the constituent elements of the samples. Notably, the H730 nanocomposite exhibited superior catalytic efficacy in comparison to its H725 counterpart for the degradation of p-nitrophenol (PNP) under both Fenton and photo-Fenton reaction conditions. Impressively, complete degradation of PNP was achieved within a remarkably short span of 18 min. Furthermore, the H730 nanocomposite alongwith stronger magnetic attributes, demonstrated a notable 86 % degradation efficiency even after undergoing five consecutive cycles.

ZnO-Cu/NiFe2O4 magnetic nanocomposite with boosted photocatalytic and antibacterial activity against E. coli.

A novel ZnO-Cu/NiFe2O4 hybrid nanocomposite with increased photocatalytic and antibacterial activities was synthesized by solid-state mixing of NiFe2O4 with Cu-doped ZnO (ZnO-Cu) and subsequent thermal processing. Various characterization techniques, like X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), Raman spectroscopy, vibrating-sample magnetometry (VSM) and Brunauer-Emmett-Teller (BET) analysis, have been used to study and characterize the synthesized nanomaterial. The XRD results demonstrated a hexagonal wurtzite phase of the ZnO nanoparticles and a reduction in the average crystallite size with doping and composite formation. The average crystallite size was found to be 32.36 ± 0.25 nm for ZnO, 29.87 ± 0.28 nm for ZnO-Cu and 24.73 ± 0.21 nm for the ZnO-Cu/NiFe2O4 nanocomposite. FESEM analysis revealed that the synthesized nanoparticles possess a nearly spherical morphology and average particle sizes of about 89 ± 1.8, 78 ± 1.9 and 63 ± 1.6 nm for the ZnO, ZnO-Cu and ZnO-Cu/NiFe2O4 samples, respectively. ZnO and ZnO-Cu/NiFe2O4 nanocomposite exhibit specific surface area of 6.67 and 12.38 m2/g, respectively, as observed from BET analysis. FTIR analysis indicated the enhancement of carboxylate and hydroxyl groups with doping and nanocomposite formation. The retentivity (Mr ∼ 0.243 emu/g), coercivity (Hc∼ 98.1 Oe) and saturation magnetization (Ms∼ 3.048 emu/g) values of the ZnO-Cu/NiFe2O4 nanocomposite, obtained from VSM analysis, confirm its superparamagnetic characteristics. To comprehend the photocatalytic activity of the prepared nanocomposite, dye degradation was also investigated. Here, we have shown that the ZnO-Cu/NiFe2O4 nanocomposite is capable of achieving the highest photocatalytic activity of 94.2% compared to ZnO (56.2%) and ZnO-Cu (86.4%). The antibacterial activity on Escherichia coli (E. coli) was investigated and the observed zones of inhibition for ZnO, ZnO-Cu and the ZnO-Cu/NiFe2O4 nanocomposite were 20.1 ± 0.21, 20.9 ± 0.20 and 27.3 ± 0.24 mm, respectively. Assuming the antibacterial activity of control ampicillin as 100%, the ZnO-Cu/NiFe2O4 nanocomposite has shown the maximum antibacterial activity of 107.5 ± 0.94% as compared to the other samples. According to our observations, the ZnO-Cu/NiFe2O4 hybrid nanocomposite exhibits the highest level of inhibition among all the samples and has the potential to be used in various environmental, biological and industrial applications.

Synthesis, optical and magnetic properties of Nd2O3/borate strontium fluoride glasses

The present work conducts the synthesis, thermal, optical, and magnetic characterization of (60-x)B2O3+20Li2O+20SrF2+ x Nd2O3 where x = 0, 0.5, 1, 1.5, 2 mol% glass samples. The samples were investigated via X-ray diffraction (XRD), Raman spectroscopy, differential scanning calorimetry (DSC), UV–Vis absorption spectroscopy, and vibrating sample magnetometry (VSM). XRD patterns for borate strontium fluoride glass samples doped with Nd2O3 showed broad humps around 30 and 43°, indicating their amorphous structure. Raman spectra of glass samples indicated that as Nd3+ ions were added to the host matrix, there was an increase in Raman intensity due to bond breakdown and the development of more non-bridging oxygen (NBO) species. The DSC data of the borate strontium fluoride glass samples doped with Nd2O3 demonstrated that the glass transition temperature (Tg) generally increased. UV–Vis absorption spectra showed transitions in Nd3+ ions doped borate glasses that are associated with the bands at different wavelengths, attributed to 4G5/2+2G7/2, 2H11/2, 4F9/2, 2H9/2 +4F5/2, and 4F3/2. The refractive index of borate strontium fluoride glass samples doped with Nd2O3 increased. The saturation magnetization values decreased from 0.9 to 0.29 upon increasing the Nd2O3 percentage (0–2 mol%). These low saturation magnetization glass samples can be used in spintronic devices to effectively reduce switching current density and lower the damping constant.

Switching of magnetic properties by topotactic reaction in a 1D CN-bridged Ni(II)-Nb(IV) system.

Two 1D CN-bridged assemblies: the nearly straight Li2[Ni(cyclam)][Nb(CN)8]·7.5H2O (1) chains and the zigzag-shaped Li2[Ni(cyclam)][Nb(CN)8]·2H2O (2) chains, are obtained in the reaction between [Ni(cyclam)]2+ and [Nb(CN)8]4- in warm concentrated LiCl water solution. Both compounds are composed of alternating bimetallic Ni(II)-Nb(IV) chains and contain incorporated lithium cations, which compensate the negative charge of the coordination skeleton. The straight chain 1 (Ni-Nb-Ni angle = 153.2°) can be reversibly dehydrated under dry nitrogen flow at room temperature to an intermediate dihydrate phase 1d and further transformed to the zigzag-shaped chain 2 (Ni-Nb-Ni angle = 86.6°) by annealing at 150 °C. The process can be reversed by exposure to high humidity at room temperature, upon which 2 is converted back to 1. This water sorption-induced breathing effect is accompanied by changes in magnetic properties, most notably reflected in different values of saturation magnetization and critical field of metamagnetic transition, which indicate that both intra- and inter-chain interactions are affected by the structure reorganization.

Enhancement in the dielectric and magnetic properties of Ni2+-Cu2+ co-doped BaFe11Cu1-xNixO19 hexaferrites (0.0 ≤ x ≤ 1.0).

Herein, Ni2+-Cu2+ co-doped barium hexaferrites (BaFe11Cu1-xNixO19, 0.0 ≤ x≤ 1.0 with an interval of 0.25) were successfully synthesized using a co-precipitation method. The formation of a magnetoplumbite structure with the P63/mmc space group was confirmed by Rietveld refinement of the obtained X-ray diffraction patterns. Microstructural investigations revealed grains in the shape of hexagonal plates, while co-doping resulted in a variation in the grain sizes of the prepared samples. X-ray photoelectron spectroscopy was performed to determine the valence state of iron in the prepared hexaferrites. Impedance spectroscopy analysis revealed that dielectric permittivity initially decreased with an increase in the co-dopant content up to x = 0.5 and then increased by two orders of magnitude for x = 1.0. Alternatively, resistive properties showed microstructural resistance values in the range 105-108 Ω, with the highest value obtained for the sample with x = 0.5. Furthermore, magnetic measurements indicated that all the prepared samples exhibited ferrimagnetic behaviour. Saturation magnetization and magnetic anisotropy values were found to be the highest for the sample with x = 1.0, which also had the lowest coercivity among the prepared samples. Herein, the observed variations in the obtained results can be explained by the variations in grain sizes and the Fe2+/Fe3+ ratio associated with the preferential occupation of co-dopants at octahedral sites. Based on our findings, the BaFe11Ni1O19 (x = 1.0) composition appears to be the most promising choice as a microwave absorption material among the prepared samples owing to the coexistence of high dielectric permittivity (>103 at 107 Hz) and saturation magnetization (73 emu g-1).