Search

Efficient conversion of ortho-hydrogen (o-H 2) to para-hydrogen (p-H 2) is crucial for liquid hydrogen development. In this work, FeMn catalysts were prepared using impregnation method and loaded onto HiSiV-3000 zeolite (FMO-H). FMO-Hs were characterized and tested for o-H 2 to p-H 2 conversion at 77 K. The results showed that 30 wt% HiSiV-3000 was the most favorable condition for the exposure of active sites of FeMn catalyst (FMO-3H). Additionally, compared to the monometallic Fe–3H catalyst, the addition of Mn increased disorder within the internal crystal structure and magnetization intensity of the catalyst, enhancing the paraffin conversion efficiency. At a gas hourly space velocity of 3600 h−1, the o-H 2 to p-H 2 conversion rate of FMO-3H reached to 98.4%, with an outlet p- H 2 content of 44.6%. [Display omitted] • Efficient FeMn-supported catalysts were prepared for ortho-para H 2 conversion. • Zeolite HiSiV-3000 facilitated the exposure of FeMn. • Mn addition enhanced the catalytic performance of Fe. [ABSTRACT FROM AUTHOR]

The effect of polyphenylene sulfide binder content on the properties of injection molding polyphenylene sulfide/NdFeB magnets were investigated. The maximum filling amount of NdFeB magnetic powder was 87.6 wt.‐%, and the mixing process and subsequent injection molding of the polyphenylene sulfide/NdFeB were in good condition. The melt mass‐flow rate of the polyphenylene sulfide/NdFeB granular materials reached 121.7 g/10 min, the compressive strength of the polyphenylene sulfide/NdFeB magnet was 92.18 MPa, and its maximum magnetic energy product reached 5.59 MGOe. The structure and morphology characteristics of polyphenylene sulfide/NdFeB magnets were investigated using scanning electron microscopy and atomic force microscopy. The corrosion behavior of polyphenylene sulfide/NdFeB magnets was also studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results indicated that the injection molding process facilitated the uniform coating of polyphenylene sulfide particles on NdFeB powder, which directly enhanced the corrosion resistance of polyphenylene sulfide/NdFeB magnets. With an increase in polyphenylene sulfide content, the surface of polyphenylene sulfide/NdFeB magnets became more uniform. The corrosion current density of 13 wt.‐% polyphenylene sulfide/NdFeB magnet was approximately one order of magnitude lower than that of 9 wt.‐% polyphenylene sulfide/NdFeB magnet, indicating an improved corrosion resistance of polyphenylene sulfide/NdFeB magnet. [ABSTRACT FROM AUTHOR]

FePBNbCr amorphous soft magnetic composites (SMCs) with high compaction density (ρ c) and commendable magnetic properties were successfully fabricated via low-pressure hot-compacting at 160 MPa. Due to the thermoplastic properties of amorphous powders in supercooled liquid region (Δ T x), the hot-compacting in the Δ T x is conducive to the increase of ρ c for the amorphous SMCs, thereby improving the corresponding soft magnetic properties via reducing the number of pinning sites. Compared with these of the cold-compacted amorphous SMCs at 600 MPa, the ρ c increases by 20.3 % to 6.04 g/cm3, the effective permeability increases by 5.26 times to 95.3, while the corresponding total core loss decreases 74.5 % to 154.4 kW/m3 (100 kHz, 0.05 T) for the amorphous SMCs hot-compacted at 495 °C with a pressure holding time of 6 min. These results indicate that the low-pressure hot compacting is an effective measure to further improve soft magnetic properties of the amorphous SMCs for rapidly adapting to the development needs of high-frequency and miniaturization of electronic devices. [ABSTRACT FROM AUTHOR]

The demand for advanced Al-based alloys with tailored structural and magnetic properties has intensified for applications requiring a high thermal stability and performance under challenging conditions. This study investigated the phase evolution, magnetic properties, thermal stability, and microstructural changes in the Al-based alloys Al82Fe16Nb2 and Al82Fe14Nb2Mn2, synthesized via mechanical alloying (MA), using stearic acid as a process control agent. The X-ray diffraction results indicated that Al82Fe16Nb2 achieved a β-phase solid solution with 13–14 nm crystallite sizes after 5 h of milling, reaching an amorphous state after 10 h. In contrast, Al82Fe14Nb2Mn2 formed a partially amorphous structure within 10 h, with enhanced stability with additional milling. Magnetic measurements indicated that both alloys possessed soft magnetic behavior under shorter milling times (1–5 h) and transitioned to hard magnetic behavior as amorphization progressed. This phenomenon was associated with a decrease in saturation magnetization (Ms) and an increase in coercivity (Hc) due to structural disorder and residual stresses. Thermal stability analyses on 10 h milled samples conducted via differential scanning calorimetry showed exothermic peaks between 300 and 800 °C, corresponding to phase transformations upon heating. Post-annealing analyses at 550 °C demonstrated the presence of phases including Al, β-phase solid solutions, Al₁3Fe₄, and residual amorphous regions. At 600 °C, the Al3Nb phase emerged as the β-phase, and the amorphous content decreased, while annealing at 700 °C fully decomposed the amorphous phases into stable crystalline forms. Microstructural analyses demonstrated a consistent reduction in and homogenization of particle sizes, with particles decreasing to 1–3 μm in diameter after 10 h. Altogether, these findings highlight MA's effectiveness in tuning the microstructure and magnetic properties of Al–Fe–Nb (Mn) alloys, making these materials suitable for applications requiring a high thermal stability and tailored magnetic responses. [ABSTRACT FROM AUTHOR]

This article investigates the relationship between the magnetic properties of magnets and the percentage and distribution of the CeFe2 phase at different sintering temperatures. At the lower sintering temperature, the grain boundary phase flow of the magnet is poor, more hole defects are generated in the magnet, and the comprehensive magnetic properties of the magnet are poor. An increase in sintering temperature increases the ratio of CeFe2 phase, improves the fluidity of grain boundary liquid phase, fills the hole defects and causes an increase in remanence. However, an increase in grain size also inhibits the coercivity of the magnet at this temperature. When the sintering temperature reaches 1080 °C, the CeFe2 phase ratio continues to increase, providing more liquid phase. The phase Ce2Fe17 was also decomposed into liquid phase, the continuity and wettability of grain boundary phase were optimized, and the coercivity reached a maximum of 13.18 kOe. However, the orientation of the magnet changed and the proportion of the main phase decreased, resulting in a slight decrease in the remanence (Br = 13.17 kGs). [ABSTRACT FROM AUTHOR]

The atomic structures, electronic structures, magnetic properties, and spin states of BiCoO3 multiferroic material under hydrostatic pressure are comprehensively investigated by using first‐principles calculation based on density functional theory. Firstly, we found the pressure‐tuned structural symmetry transition from tetragonal P4 mm (No. 99) to cubic Pm3¯$\bar{3}$m (No. 221) space group. The structural transformation prompts the Co─O polyhedral coordination transfer from a CoO5 pyramidal to a CoO6 distorted octahedron. Secondly, the pressure‐induced magnetic change from C‐type antiferromagnetic state to ferromagnetic state and then to paramagnetic configuration occurred after continuous compression of the volume. Essentially, the fundamental reason for the transition of the magnetic structure lies in the change of the internal atomic structure, such as the pressure induced abrupt changes of Co─O bond length and bond angle. Meanwhile, an obvious volume collapse was observed when the pressure was applied to 51–56 GPa. Finally, as the pressure increases, the magnetism changes from C‐type antiferromagnetic state to paramagnetic configuration, accompanying the transformation from high spin state with b2g2eg2a1g1b1g1 configuration in pyramid structure to low spin state with t2g6eg0 in octahedral field. Therefore, our results demonstrate that applied hydrostatic pressure in BiCoO3 can trigger the transformation of structure, magnetism, charge, and spin state. [ABSTRACT FROM AUTHOR]

Planar hypercoordinate motifs represent an intriguing frontier in chemistry, challenging traditional bonding norms. As electronegativity of the central atom increases, achieving planar hypercoordination becomes more difficult due to restricted delocalization, making the design of planar hypercoordinate halogens particularly puzzling. Here, we conduct an extensive computational survey of LinXn+1− (n=4, 5, 6; X=F, Cl, Br, I) clusters, revealing a starlike D5h‐symmetry global minimum in Li5X6− (X=F, Cl, Br) with a planar pentacoordinate halogen (ppX), where X− is located at the center of Li5X5 crown. The clusters are stabilized predominantly through electrostatic interactions between X− and Li5X5, complemented by weak covalent bonding from dative interaction. Due to the weak orbital overlap, ppX clusters exhibit localized diatropic ring currents around X and Li. [ABSTRACT FROM AUTHOR]

In this study, a feasible strategy, named hydrogen mineral phase transformation (HMPT) technology, is proposed and employed to achieve efficient and clean recovery of Hainan Shilu refractory iron ore (HSRIO). The influences of HMPT roasting temperature, roasting time, and H 2 concentration on the separation index of HSRIO are investigated. Under the optimal experimental conditions, the iron concentrate grade increases from 62.5% to 67.9%, and the iron recovery increases from 65.0% to 94.7% compared with the original beneficiation process. In addition, the evolution of mineral phases, magnetic properties, and mineral microstructures is analyzed using XRD, VSM, SEM, and high-temperature hot-stage microscopy. It is revealed that the transformation of hematite to magnetite occurs during the HMPT process, with the newly formed magnetite exhibiting a loose and porous reticulation structure. This study is of guiding significance for the development of Hainan Shilu refractory iron ore with high efficiency and zero-carbon emission. [Display omitted] • Efficient recovery of HSRIO achieved through environmentally friendly HMPT technology. • Precise phase control enhances mineral magnetism, thereby promoting iron ore recovery. • The reduction reaction of the mineral proceeds from the surface inward. • This study provides theoretical support for the industrial production of HMPT. [ABSTRACT FROM AUTHOR]

The utilization of magnetoelectric composites, particularly core-shell configurations, enhances their versatile applications in various sectors such as medicine and data storage. Among these composites, the perovskite-spinel combination is distinguished by its significant potential. A series of (1-x) BiFeO 3 -(x) CoFe 2 O 4 (where x = 0.0, 0.2, 0.5, and 1.0) nano core-shell structures were synthesized using a sol-gel auto-combustion method to explore their multifunctional capabilities. Structural analyses identified peaks corresponding to both perovskite and spinel phases. Field Emission Scanning Electron Microscopy revealed a reduction in average particle size with an increase in CoFe 2 O 4 content.The particle size in the BFO80-CFO20 sample has been reduced from 243 nm to 34 nm. Additionally, Transmission Electron Microscopy images of the BFO80-CFO20 sample highlighted the evolution of core-shell structures. Our findings indicate that higher CFO concentrations significantly affect the dielectric, ferroelectric, and optical properties. The bandgaps of the nanocomposites BFO80-CFO20 and BFO50-CFO50 were estimated to be 1.43 eV and 1.39 eV, respectively. Magnetic analysis showed increases in both saturation magnetization and remanent magnetization with increased CFO content, while the coercive field followed a different trend. The saturation magnetization values for the samples BFO, BFO80-CFO20, BFO50-CFO50, and CFO were calculated as 0.205, 14.612, 28.374, and 74.105 (e m u g r) , respectively. The measured values for the same samples were 0.08, 5.07, 11.34, and 34.01 (e m u g r) , respectively. Further, the electrochemical properties were thoroughly investigated using cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. [ABSTRACT FROM AUTHOR]

In order to improve the microwave-absorption performance of barium ferrite and broaden its microwave-absorption band, BaFe12O19, Ba0.95Ca0.05Fe12O19, and Ba0.95Ca0.05Fe12−xCoxO19 (x = 0.1, 0.2, 0.3 and 0.4, respectively) hexaferrites were synthesized by the solid-state reaction method, and the influence of Co ion substitution on the phase composition, microstructure, magnetic properties, and microwave-absorption ability of the ferrites in this system was studied. Introducing minor Co ions (x < 0.2) facilitated sintering and grain growth. At x ≥ 0.2, XRD revealed the emergence of the Co2X phase alongside the BaM phase. Increasing Co ion concentration and the secondary X-phase led to slight reductions in saturation magnetization (69 to 63.5 emu/g) and substantial decline in coercivity (2107.02 to 111.21 Oe), attributed to grain size growth and Co2X's soft magnetic nature. Notably, Co2X incorporation significantly enhanced the microwave absorption and provided a tunable absorption band from the Ku to the C band. For a sample with a thickness of 2.0 mm and a doping level of x = 0.2, a minimum reflection loss of −59.5 dB was achieved at 8.92 GHz, with an effective absorption bandwidth of 3.31 GHz (7.07–10.38 GHz). The simple preparation method and good performance make Ba0.95Ca0.05Fe12−xCoxO19 (x = 0.1, 0.2, 0.3 and 0.4, respectively) hexaferrites promising microwave-absorbing materials. [ABSTRACT FROM AUTHOR]

An effective method to improve the magnetic properties of soft-magnetic composites (SMCs) is insulation coating, which is achieved by inducing an interfacial solid-phase reaction via hot-pressing sintering. Herein, an interfacial solid-phase reaction was induced at the SMC interface through salt compound decomposition and the doping of carbonyl iron powder (CIP). Furthermore, FeSiAl-based SMCs with various CIP amounts were prepared. Results show that during hot-pressing sintering, calcium acetate coated on the FeSiAl matrix decomposes. Furthermore, the generated reactive oxygen species cause Si and Al migrations to the heterogeneous interface; in combination with the decomposition product CaO, these migrations result in the in situ formation of a CaSiO 3 ·SiO 2 ·Al 2 O 3 composite insulation layer on the matrix surface. CIP added to the hydrothermal insulation coating exhibits good plasticity, and its combination with the coating layer improves the compressibility of composite powders and eliminates pores within SMCs. In hot-pressing sintering, CIP addition hinders the conversion of Si to SiO 2 , resulting in excess reactive oxygen species that react with Al in the FeSiAl matrix to yield a higher Al 2 O 3 content. With an increase in the CIP amount, more Si diffuses into CIP such that the magnetic phase inside FeSiAl-based SMCs changes from a single Al 0.3 Fe 3 Si 0.7 phase to a mixed phase comprising an Al 0.3−x Fe 3 Si 0.7−y phase, CIP and CIP–Si. However, excessive CIP addition can cause the re-formation of pores inside SMCs and deterioration of magnetic properties. By changing CIP addition amounts, the magnetic properties of SMCs are precisely regulated. When the CIP addition amount is 9 wt%, the prepared SMCs exhibit optimal magnetic properties, with the highest saturation magnetisation of 134.5 emu/g and permeability of 44.1 at 10 mT and 500 kHz, along with a core loss as low as 198.8 kW/m3 at 20 mT and 100 kHz. [Display omitted] [ABSTRACT FROM AUTHOR]

Two tetranuclear Co(II) complexes, [Co4(pmab)4Cl4] (1) and [Co4(pmab)4(OBz)2]Cl2 (2) [Hpmab = 2-{(p-pyridinylmethylene)amino}benzenemethanol], have been synthesized and characterized through single-crystal X-ray diffraction, IR and UV-VIS spectroscopy, and magnetic measurements. Structural analysis revealed that both complexes possess a [Co4O4] cubane-like metal core connected by μ3-alkoxo bridges. Magnetic measurements of Complex 1 indicate weak ferromagnetic interactions (J ~ +0.75 cm−1) within the tetranuclear core, while Complex 2 exhibits antiferromagnetic behavior due to the presence of syn-syn bridging benzoate ligands. Alternating current (AC) magnetic measurements suggest that Complex 1 exhibits slow magnetic relaxation behavior. [ABSTRACT FROM AUTHOR]

This study aimed to enhance the surface defects and fluorescence properties of GdPO₄·H₂O:Tb³⁺ nanophosphors and develop a nanoscale dual-layer core-shell structured fluorescent probe, GdPO₄·H₂O:20%Tb³⁺@GdPO₄@PEG. Hydrothermal and microwave synthesis methods were employed. The former controlled the ratio of GdPO₄·H₂O:Tb³⁺ to GdPO₄, forming core-shell structured nanophosphors GdPO₄·H₂O:20%Tb³⁺@GdPO₄ with varying shell thicknesses. The latter involved Polyethylene Glycol (PEG) as a surface modification agent, resulting in a high-performance dual-layer fluorescent nanomaterial, GdPO₄·H₂O:20%Tb³⁺@GdPO₄@PEG. We characterized the modified and unmodified fluorescent powders for their structural, morphological, optical, and magnetic properties using XRD, SEM, TEM, FTIR, TG, FL, and VSM techniques. Both pre- and post-coated nanophosphors exhibited a singular hexagonal crystal structure with an ellipsoidal morphology, average particle sizes of approximately 40–50 nm, and coating layer thicknesses of about 5–15 nm. The excitation and emission peak positions remained relatively constant before and after the coating process. The dual-layer core-shell nano-fluorescent probe demonstrated significantly enhanced fluorescence intensity due to reduced non-radiative transition rates. Moreover, both pre- and post-coated nanophosphors exhibited excellent paramagnetic properties. This research successfully improved the hydrophilicity and biocompatibility of GdPO₄·H₂O:Tb³⁺ nanophosphors while concurrently enhancing their luminescent and magnetic performance. [ABSTRACT FROM AUTHOR]

Oxygen evolution and reduction reactions (OER and ORR) play crucial roles in energy conversion processes such as water splitting and air batteries, where spin dynamics inherently influence their efficiency. However, the specific contribution of spin has yet to be fully understood. In this study, we intentionally introduce a spin channel through the transformation of trigonal antiferromagnetic SrCoO2.5 into cubic ferromagnetic SrCoO3, aiming to deepen our understanding of spin dynamics in catalytic reactions. Based on the results from spherical‐aberration‐corrected microscopy, synchrotron absorption spectra, magnetic characterizations, and density functional theory calculations, it is revealed that surface electron transfer is predominantly governed by local geometric structures, while the presence of the spin channel significantly enhances the bulk transport of spin‐polarized electrons, particularly under high current densities where surface electron transfer is no longer the limiting factor. The overpotential for OER is reduced by at least 70 mV at 150 mA cm−2 due to the enhanced conductivity from spin‐polarized electrons facilitated by spin channels, with an expectation of even more significant reductions at higher current densities. This work provides a clearer picture of the role of spin in oxygen‐involved electrocatalysis, providing critical insights for the design of more efficient catalytic systems in practical applications. [ABSTRACT FROM AUTHOR]

The structural, microstructural, dielectric, optical, ferroelectric, and magnetic properties of cobalt doped barium calcium titanate (BCT) (Ba 0.80 Ca 0.20 Ti 1-x Co x O 3 with x = 0.000, 0.005, 0.010, 0.015, and 0.020) ceramics have been reported in this paper. The ceramic samples were prepared by the conventional solid-state reaction method. For all of the prepared samples, the tetragonal structure with the space group P 4 mm has been confirmed using the refinement method through Rietveld refinement of X-ray diffraction patterns. Field Emission Scanning Electron Microscopy (FESEM) micrographs revealed that the average particle size exists in micrometre range (0.3–0.8) μm. Optical studies revealed a gradual decrease in the energy bandgap from 3.31 eV to 2.71 eV with increasing doping concentration. A decreasing trend was observed in the dielectric characteristics of the material with changing frequencies at room temperature. Ferroelectric (P-E loops) analysis displayed an increase in both remnant polarization and maximum polarization of the ceramic with the increasing applied electric field. The highest value for the energy storage efficiency (η) was calculated to be 20.51 %. Magnetic analysis conducted at room temperature revealed the enhancement in ferromagnetism with the increase in doping concentration. [ABSTRACT FROM AUTHOR]

MnZn ferrite powders were prepared based on the novel nano in situ composite method and through chemical sol-spray drying–calcination technology. The precursor powders were calcined at 1060 °C at different calcination times (1–9 h) to research the influences of the calcination time on MnZn ferrite powders. The research results revealed that all samples had similar morphologies composed of fine particles. The pure MnZn ferrite spinel phase can only be obtained when the calcination time does not exceed 3 h. Otherwise, some α-Fe2O3 or γ-Fe2O3 impurities will appear. The particle size descended with an increasing calcination time and then ascended. After 3 h of preservation, the smallest particle size was obtained, and it exhibited a unimodal distribution. The saturation magnetization (Ms) increased at first and decreased later with an increasing calcination time, and the optimal value (53.4 emu/g) was reached after holding for 3 h. In view of this work, the optimal calcination time is 3 h. [ABSTRACT FROM AUTHOR]

To meet the needs for higher energy efficiency and a wide operating temperature range of electric vehicles, the low‐loss MnZn ferrites in a wide temperature range have been developed by optimizing the Fe content and the oxygen partial pressure (PO2) during the sintering process in this work. For the optimal sample, power loss at 300 kHz/100mT is 204 kW/m3 at 25°C and remains below 290 kW/m3 in the wide temperature range from ‐10 to 120°C. The loss separation method was employed to clarify the effects of the Fe content and PO2 on power loss. The equivalent circuit model has been employed to fit the complex impedance and it is found that the increase of PO2 enhances both the grain resistance Rg and the grain boundary resistance Rgb. The enhancement of Rgb is mainly responsible for the reduction of eddy current loss and consequently power loss. Dielectric permittivity is as large as about 15000 in this series of samples due to the electric polarization at the rich grain boundaries. Dielectric loss is very low between ‐50 and 150°C and has little contribution to the energy loss. [ABSTRACT FROM AUTHOR]

In this study, the sol-gel synthesis technique was harnessed to craft nanocomposites of (1-x)La 0.7 Sr 0.3 MnO 3 -(x)BTO with x values of 0.4, 0.6, and 0.8. The attributes of these meticulously engineered materials were exhaustively explored using a diverse suite of characterization methods. X-ray diffraction analysis irrefutably confirmed the phase purity of the perovskite structure, emphasizing the synthesis's precision. Furthermore, Diffuse Reflectance Spectroscopy shed light on the optical properties of the nanocomposites, revealing a significant shift in bandgap energy that correlated directly with the BTO concentration. Specifically, an increment in BTO concentration resulted in a systematic expansion of the bandgap from 1.51 eV to 1.44 eV. For an in-depth analysis of the magnetic characteristics of the composites, Vibrating Sample Magnetometry was utilized. The magnetic analysis identified a conspicuous reduction in saturation magnetization, highlighting the complex interplay between the composite components at the nanoscale. Additionally, the dielectric properties were rigorously investigated through dielectric measurements, which unveiled a notable increase in the dielectric constant, accompanied by the emergence of novel relaxation behaviors. This finding indicates that adjusting the BTO content within the nanocomposites not only modifies their dielectric properties but also provides a method for fine-tuning their functional performance. [ABSTRACT FROM AUTHOR]

The susceptibility of either oxidation into Sn(IV) or disproportionation into Sn(IV) and Sn(0) limits the study of metal tin‐(II)‐borate ceramics. We report mullite‐type SnCrBO4 and SnVBO4 synthesized in sealed quartz tubes by conventional solid‐state method. X‐ray powder diffraction data Rietveld refinements confirm that both compounds are isostructural to PbMBO4 phases for M = Al, Ga, Cr, Mn, and Fe. The end‐members show a complete miscibility within the Sn(Cr1−xVx)BO4 solid solution. Both the microstructural (average crystallite size, microstrain, and degree of crystallinity) and crystal structural (metric parameters, bond lengths, polyhedral volume, and polyhedral distortion) parameters are observed with respect to the compositional x‐value. The stereochemical activity of the 5 s2 lone electron pairs of Sn2+ cations has been measured by using the Wang–Liebau eccentricity parameter. The structural features are complemented by 119Sn Mössbauer, Raman, and Fourier‐transformed infrared spectroscopy. The 119Sn Mössbauer isomer shifts and the quadrupole splitting values confirm the SnO4 coordination and an Sn(II) valence state. The electronic band gap has been calculated from the UV/Vis diffuse reflectance spectra, which slightly increases with successive decrease of the cationic radius from V to Cr. Temperature‐dependent inverse DC magnetic susceptibility suggests that SnCrBO4 and SnVBO4 are antiferromagnetic and ferromagnetic (FM) with a Néel temperature of 17.2(1) K and a Curie temperature of 29.8(1) K, respectively. Alike the end‐member SnVBO4, Sn(Cr0.5V0.5)BO4 is also found to be a rare FM insulator. The thermal stability decreases with increasing vanadium content in the solid solution. [ABSTRACT FROM AUTHOR]

M-type hexagonal ferrites have received widespread attention for their excellent magnetic properties, but studying the intricate interplay between their composition, process and magnetic properties has long been a puzzling task. The advent of machine learning offers a promising example for accelerating the discovery of connections between them. In this work, we trained five machine learning regression models (SVR, DTR, AdaBoost, GBDT and MLP) using data collected from the literature and found that the SVR model performed well on the dataset. In order to verify the feasibility of the SVR model, we predicted the magnetic properties of Ba 1-x La x Fe 12-y Mn y O 19 (0.1≤x=y≤0.6), and then prepared and tested them. The results showed a good agreement between the prediction and the experiment, which proved the reliability of the designed model. Moreover, we elucidate the occupancy trend of Mn3+ ions by first principles calculation and Raman spectroscopy verification. This work strongly suggests that machine learning has the potential to explore the relationship between composition, process and properties, which opens the door for the tailoring the properties of M-type hexagonal ferrites. [ABSTRACT FROM AUTHOR]

Cu80Co20/CNT nano-composites were prepared by mechanical alloying for various duration of time. The effects of CNT addition on Co solid solubility in Cu morphology, magnetic and electrical characteristics of the samples were analyzed using state-of-the-art methods, such as x-ray diffraction (XRD), differential thermal analyzer (DTA), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), superconducting quantum interference device (SQUID) and four point probe technique, respectively. In a sample that was milled for 10 h, it was demonstrated that the solid solubility of Co in Cu increased to 20 wt.%; however, CNTs in Cu80Co20/CNT nano-composites prevented this from happening. 10 h after mechanical alloying, CNTs were uniformly dispersed throughout the metal matrix, and the resulting products were agglomerates of nanoparticles. The addition of CNTs changed the magnetic properties of nano-composite samples, according to analysis of magnetic hysteresis loops. The saturation magnetization and coercivity of composite samples increased with increasing CNT content because of the non-dissolved paramagnetic Co in nano-composites and the exchange coupling phenomenon. Cu-Co/CNT nano-composites' electrical resistance increased with CNT concentration. [ABSTRACT FROM AUTHOR]

Electrospinning technology is widely used for preparing biological tissue engineering scaffolds because of its advantages of simple preparation, accurate process parameters, and easy control. Poly(L-lactide) (PLLA) is regarded as a promising biomass-based polymer for use in electrospinning. The incorporation of Fe3O4 nanoparticles (NPs) could improve the osteogenic differentiation and proliferation of cells in the presence or absence of a static magnetic field (SMF). In this work, these two materials were blended together to obtain electrospun samples with better dispersibility and improved magnetic properties. First, composite PLLA and Fe3O4 NP fibers were prepared by means of electrospinning. The influence of electrospinning conditions on the morphology of the composite fibers was then discussed. Changes in magnetic properties and thermal stability resulting from the use of different PLLA/Fe3O4 mass ratios were also considered. Next, the morphology, crystal state, thermodynamic properties, and magnetic properties of the electrospun samples were determined using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and vibration sample magnetization (VSM). The results showed that the fibers prepared using PLLA with Mn = 170,000 exhibited good morphology when electrospun at 12 KV. The magnetic properties of PLLA/Fe3O4 composite electrospun fibers increased with the NP content, with the exception of thermal stability. The results of the present study may help to promote the further development of PLLA/Fe3O4 composite materials in the biomedical field. [ABSTRACT FROM AUTHOR]

In this study, we successfully fabricated Fe61Zr10Co5Mo7W2B15 and Ni61Nb19.2Ta19.8 amorphous fibers (AFs) using the melt-extraction method. This method ensured a rapid cooling, uniform quality, minimal defects, and superior performance. Magnetic property analysis revealed that the Fe-based AFs exhibited a single-slope magnetization curve characteristic of paramagnetic or diamagnetic materials, while the Ni-based AFs displayed a rectangular curve with low magnetic hysteresis, typical of ferromagnetic materials. The axial saturation magnetization of as-prepared Ni-based AFs is ~1.5 × 10−7 emu/g, with a coercivity of about 85 Oe. The statistical analysis of tensile tests indicated that Ni-based AFs possess a higher fracture threshold of 2440 ± 199 MPa and a reliability of 14.7, demonstrating greater material safety and suitability for high-performance applications. As opposed to Ni-based AFs, Fe-based AFs present a fracture threshold and of 1582 ± 692 MPa and a reliability 4.2. Moreover, under cyclic loading conditions, Ni-based AFs exhibited less residual deformation and superior elastic recovery with a fracture strength of 2800 MPa. These findings highlight the potential of Ni-based AFs for advanced engineering applications, particularly where high strength, durability, and excellent magnetic properties are required, paving the way for their integration into next-generation technologies. [ABSTRACT FROM AUTHOR]

Carboxylato-bridged dinuclear and tetranuclear Mn(II) complexes 1–3 with ditopic ligands featuring two N3-terminal coordination sites connected by hexyl (tphn), octyl (tpon), and p-xylyl (tpxn) linkers have been synthesized and characterized through X-ray single-crystal structure analyses, infrared spectroscopy, and elemental analyses. Complex 1 is a μ-fluorido-bis-μ-acetato dinuclear Mn(II) complex where the ligand tphn coordinates to both terminal sides of a dinuclear Mn unit. In contrast, complexes 2 and 3 are tetranuclear Mn(II) complexes with a macrocyclic structure, in which two dinuclear Mn units are linked by ligands tpon or tpxn. The redox behaviors of 1 and 2 were elucidated by cyclic voltammetry, revealing two metal-centered redox processes corresponding to Mn2(II,II)/Mn2(II,III) and Mn2(II,III)/Mn2(III,III). [ABSTRACT FROM AUTHOR]

Using first-principles calculations based on density-functional theory, this paper investigates the electronic structure and magnetic properties of the Heusler alloy Mn2LiGe bulk and its (001) surfaces. The Mn2LiGe bulk is demonstrated to be inverse Heusler alloy with space group of F43m and lattice constant of 5. 87 Å. A direct band gap with a width of 1. 1 eV near the Fermi surface of the spin-down channel is detected. The Mn2LiGe bulk possesses stable half-metallic and magnetism in the lattice constant range of 5. 55 - 6. 33 Å. In addition, six different surface structures of Mn2LiGe are constructed in this paper. The first layer atoms on the surface undergo different displacements, increasing the surface roughness. Due to surface effects, the magnetic properties of atoms on the surface are different compared to those in the bulk. Both the MnA MnA and MnB MnB surface structures have the highest magnetic moments, while the LiLi and the GeGe surface structures have the lowest magnetic moments. Electronic structure calculations show that the half-metallic band gap present in the bulk is destroyed in all six surface structures and the spin polarization is weakened in varying degrees. Only the LiLi surface structure maintains up to 99. 9% of the surface spin polarization, making the surface an excellent prospect for applications in spintronic devices. [ABSTRACT FROM AUTHOR]

This study explores the remarkable properties of liquescent open‐shell ionic molecular systems, emphasizing the magnetic and photophysical characteristics arising from their associated structures in the condensed state under various conditions. Well‐investigated open‐shell molecules, namely, phenothiazine, dihydrophenazine, and tetrathiafulvalene radical cations, and bis(malononitriledithiolato)nickel(III) anionic complexes were examined, and the concept of liquescent open‐shell ionic molecular systems was devised. Transformations in their associated structures are induced by external stimuli, resulting in significant variations in their physical properties. These experimental findings open new avenues for exploring and applying stimuli‐responsive molecule‐based materials. [ABSTRACT FROM AUTHOR]

Summary: Half-metallic materials are widely used as spintronic devices such as electrodes, magnetic tunneling junction, and giant magnetoresistance. In this work, we have systematically investigated the structural stability, Gilbert damping, electronic structure, and magnetism together with exchange interactions and Curie temperatures for Mn2TaAl and Mn2WAl alloys. Initially, we estimate their structural stability and offer possible phase synthesis. Subsequently, the Gilbert damping parameters calculated by the linear response theory are used to assess their response speed as spintronic materials. Furthermore, the Mn2TaAl and Mn2WAl are predicted to be half-metallic and nearly half-metallic ferrimagnets and their total magnetic moments obey the Mt = Zt-18 rule. Accordingly, their Curie temperatures for Mn2TaAl and Mn2WAl are also evaluated by the mean-field approximation. Finally, their thermodynamic parameters within 0∼600 K and thermoelectric properties within 200∼900 K are discussed. Overall, our research for Mn2TaAl and Mn2WAl alloys might provide some valuable clues for their application in spintronic devices.

The structural, electronic, magnetic, and optical properties of Co-doped 10–20-atom silver clusters are investigated by GGA/PBE via the density functional theory. The Ag–Co clusters form core–shell structures with a Co atom in the center. Co atom doping modulates electronic properties like energy gap, molecular softness, global hardness, electronegativity, and electrophilicity index. For the optical spectra of the Ag–Co clusters, the energy of their spectra overall exhibits little change with increasing numbers of atoms; the strongest peaks are roughly distributed at 3.5 eV, and the intensity of their spectra overall is strengthened. Raman and vibrational spectra reflect structural changes with Co atom addition. The addition of the Co atom alters magnetic moments of specific Ag–Co clusters, while others remain unchanged. [ABSTRACT FROM AUTHOR]

The alloy 50Ag−50Mn (wt.%) was prepared using ball milling. After 50 h of milling, the samples were isothermally annealed for 1 h at a time at three different temperatures ranging from 350∘C to 550∘C. By analyzing the X-ray diffraction data, Rietveld refinement structure analysis was used to measure the lattice strain and crystallite size. The introduction of lattice strain and the decrease in crystallite size as a function of milling time may both contribute to the increase in coercivity. The analysis of superconducting quantum interference devices demonstrates the soft ferromagnetic behavior of as-milled and annealed Ag−Mn alloy. After being annealed at 350∘C for 1 h, the 50Ag−50Mn alloy's maximum coercivity was discovered to be 253 Oe. [ABSTRACT FROM AUTHOR]

A cobalt ferrite (CoFe2O4) nanoparticle is harvested through sol–gel method. The various percentage of PVP (2.5, 5.0, 7.5, 10.0 and 12.5%) was added to the initial solutions and is acted as a chelating agent. Through X-Ray diffraction examinations results confirmed the single phase CoFe2O4 and had bigger crystallite size. The functional analysis is found through Fourier transform infrared spectroscopy (FTIR) studies. The optical analysis carried out through UV–visible spectrometer and a direct bandgap were determined. The surface features and its content of elements in the samples were found through scanning electron microscope (SEM) with energy dispersive (EDAX) analysis. The detailed magnetic characteristics of the resulting sample were found through vibrating sample magnetometer (VSM). Through TG/DTA measurements the decompositions and anionic oxidation—reduction were analysed. The dielectric constant and related parameters with respect to applied frequency are discussed through LCR measurement. The electrochemical behavior of the samples was tested through cyclic voltameter setup. And finally concluded with the merits and demerits. [ABSTRACT FROM AUTHOR]

The synthesis of SnO2 nanoparticles doped with varying concentrations of Fe was carried out using the sol–gel method. The resulting samples underwent analysis using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), ultraviolet–visible spectroscopy (UV–Vis), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy, and vibrating sample magnetometry. The purpose of this investigation was to examine the impact of doping on the structural, optical, and magnetic properties of the nanoparticles. The XRD study demonstrated a discernible alteration in the size of the crystalline structure as a function of the concentration of doping. The study revealed a noticeable variation in crystallite size, ranging from ~ 13 to 5 nm, as the Fe doping concentration increased from 0 to 7 mol%. This observation suggested that the rise in Fe content effectively hindered crystal development. The estimation of the optical band gap was performed using the Kubelka–Munk equation, revealing a decrease in the band gap for a specific doping concentration of Fe. The photoluminescence (PL) spectra obtained at room temperature indicated a red shift in the peak positions of the pristine SnO2 samples upon Fe doping. This observation provides confirmation of the reduction in the band gap of SnO2 resulting from the incorporation of Fe dopants. The nanoparticles doped with 5% Fe exhibited superior optical characteristics compared to the remaining samples. Furthermore, magnetic properties were determined by investigating magnetization vs. applied fields. Ferromagnetic interaction was observed in all the systems of SnO2 doped with Fe. To achieve a comprehensive understanding, the utilization of density functional theory was employed. The electronic states and density of states behavior were computed to accurately anticipate the arrangement of lattice sites and the corresponding presence of atoms. Theoretical computations were conducted using the VASP program. [ABSTRACT FROM AUTHOR]

Herein, Fe–Si–Al-based soft magnetic composites (SMCs) doped with carbonyl iron powders (CIPs) at different concentrations were successfully prepared. The reaction between CIPs and core–shell Fe–Si–Al/SiO 2 heterogeneous composite powders, induced by the high temperature and concentration gradient during heat treatment, was investigated. The effect of doping CIPs at different concentrations on the microstructure and magnetic properties of Fe–Si–Al-based SMCs was also studied. During heat treatment, the Fe–Si–Al/SiO 2 powders inside the SMCs exhibited a complex reaction with the doped CIP. The reaction involved multidirectional migration of Al and Si, evolution of an Al 2 O 3 + SiO 2 -composite insulating layer and formation of composite ferromagnetic phases. Furthermore, the density, saturation magnetisation, permeability and core loss of Fe–Si–Al-based SMCs were improved by doping the composites with moderate amounts of CIPs. The Fe–Si–Al-based SMCs doped with 8-wt% CIPs exhibited the best comprehensive magnetic properties (permeability = 43.5, saturation magnetisation = 160.1 emu/g and core loss = 481.7 kW/m3 at 10 mT and 100 kHz). Compared with undoped Fe–Si–Al-based SMCs, the permeability and saturation magnetisation increased by 40.3% and 24.0%, respectively, and the core loss decreased by 18.8%. Thus, the proposed method can effectively address the restrictive relation problem between permeability and energy loss in these composites. [Display omitted] [ABSTRACT FROM AUTHOR]

Considering the high-speed and high power density technical specifications of new energy vehicle motors, there is a growing demand for rotor strength as motor peak speeds reach 20,000 r/min and beyond. The utilization of non-oriented silicon steel with a high yield strength in rotors has emerged as a promising approach to increase motor speed. However, the magnetic and mechanical properties of high-strength silicon steel under variable temperature conditions have not been fully explored, particularly in regards to their impact on motor torque, efficiency, and speed. This manuscript investigates the behavior of high-strength silicon steel before and after annealing and at different temperatures, analyzing its influence on high-speed motor performance. The validity and feasibility of this study are confirmed through prototype testing, providing a comprehensive reference for engineering design. [ABSTRACT FROM AUTHOR]

This study investigates the structural and magnetic properties of pyrochlore Lu 2 V 2 O 7 material. The ferromagnetic transition in pyrochlore Lu 2 V 2 O 7 has been confirmed at a Curie temperature (Tc = 73 K). In addition, the Raman spectrum is measured to introduce structural material observation. Raman investigations demonstrate that many vibrational motions are observed in the pyrochlore system. The Raman spectra were taken between 78 and 295 K and a frequency range of 100–1200 cm−1. In Raman measurement, the Lu 2 V 2 O 7 sample exhibits four different vibrations. All vibrational modes show temperature dependence. At room temperature, the first two peaks (A and B) appeared at lower spectrum (152.7 cm−1 and 227.5 cm−1), respectively, and the last two peaks (C and D) are observed at higher spectrum (307.1 cm−1 and 524.9 cm−1) ( 307.1 cm - 1 and 524.9 cm - 1 ). The magnetization measurement confirmed that the ferromagnetic transition occurred at a Curie temperature of Tc = 73 K. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Regulating spin crossover (SCO) behavior, especially controlling the spin transition steps, is an important scientific issue, mainly because people aim to control spin bistability and multistability. Presently, SCO bistability can be regulated by changing the ligand‐modifying species, non‐coordinated anions, guest molecules, and metal‐ion dopant. However, the control of multistability is extremely challenging, especially in Fe(III) SCO compounds. Here, we report that [FeIII(H‐5‐Br‐thsa)(5‐Br‐thsa)]·H2O (5‐Br‐thsa = (5‐bromo‐2‐hydroxybenzylidene)hydrazinecarbothioamide), a compound we have reported before, exists in two polymorphic forms: polymorph 1 exhibits three‐step SCO, and polymorph 2 shows five‐step SCO, with multi‐step SCO behavior effectively regulated by polymorphism. According to single‐crystal and powder X‐ray diffractometry, polymorphs 1 and 2 crystallize in different space groups during their spin transitions, with two‐step symmetry breaking observed (Pbcn → Pnc2 → Pbcn for polymorph 1; P21/n → Pn → P21/n for polymorph 2). We realized that the behavior of these two polymorphs depends significantly on the structure, including (i) the average Fe—N bond distance, (ii) deformation of octahedral FeIII atoms, and (iii) distinct crystal packing, which account for the large differences observed in magnetic properties. [ABSTRACT FROM AUTHOR]

Sm2Fe17N3 powder exhibits excellent magnetic properties but is unstable and decomposes into α-Fe and SmN phases at high temperatures. Therefore, the key to producing Sm2Fe17N3 bulk magnets is to reduce the deterioration of Sm2Fe17N3 powder during sintering. Herein, Sm2Fe17N3 bulk magnets were made using the spark plasma sintering (SPS) method with the addition of zinc stearate powder and zinc powder. Adding small amounts of zinc stearate powder and zinc powder improved the magnetic anisotropy and the coercivity of the magnets, respectively. The magnets produced by the SPS method using zinc stearate powder and zinc powder exhibited enhanced magnetic properties almost comparable to those of Sm2Fe17N3 powder. [ABSTRACT FROM AUTHOR]

A new molybdovanadate-based heterometallic complex, (NH4)17.5[Co0.5Na0.5(H2O)3]2[Co(H2O)4]2[(Cu6(H2O)2(OH)2V9Mo23O108)]·23.5H2O (1), was synthesized through the sequential-synthetic method and fully characterized. Structural analysis reveals that compound 1 exhibits a two-dimensional (2D) framework constructed from the C-shaped {V9Mo23Cu6} anions connected by [Co(H2O)4]2+ and [Co0.5Na0.5(H2O)3]1.5+ units. Compound 1 has a columnar structure with a smooth surface, sharp fringes, and an average size of 40 nm. Photophysical studies show that compound 1 has a band gap of ca. 2.13 eV. Magnetic studies reveal the presence of strong antiferromagnetic interactions in compound 1. A new molybdovanadate-based heterometallic complexes constructed from the C-shaped {V9Mo23Cu6} clusters linked with [Co(H2O)4]2+ and [Co0.5Na0.5(H2O)3]1.5+ units has been synthesized. Compound 1 has a band gap value of ca. 2.13 eV and exhibits the dominant antiferromagnetic behavior. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bi1−xEuxFe0.95Co0.05O3 (x=0.05, 0.10, 0.15, and 0.20) nanoparticles were prepared through the sol-gel technique. Its structure, local electronic structure, magnetic and electric properties were systematically investigated. X-ray diffraction data show (104), (110) bimodal alignment and high angular migration, indicating that with the increase of Eu substitution at Bi site, the structure of BFO undergoes a continuous change in crystal structure. The hysteresis loop and the FC/ZFC curve show how magnetism varies with the size of the field and temperature. Finally, the causes of magnetic changes were analyzed by studying SXAS and hysteresis loops. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The variation rule of deformation structure and magnetic properties of high strength non-oriented electrical steel with cold rolling were studied by field emission scanning electron microscopy(SEM+EBSD), rapid temperature tube furnace and AC magnetic properties measuring instrument. The results show that the rough strips with a large number of substructures and smooth strips with a small amount of deformation are formed in cold-rolled high strength non-oriented electrical steel. The rough strip has a γ orientation, mainly {111}〈110〉, and the smooth strip has a {112}〈110〉 and {001}〈110〉 orientation. In the rough strips, there are a lot of shear bands with width of about 2-3 μm, which show an angle of 20°-35°to the rolling direction. And the quantity increases gradually with the increase of the reduction rate. There is a certain misorientation between the shear band and the matrix. With the increase of the reduction rate, the shear band gradually changes from {111}〈110〉 to {223}〈110〉, and the misorientation between the shear band and the matrix gradually increases. After annealing, the texture of Goss and {111} increases, while the texture of {001} decreases. The rolling direction magnetic induction intensity increases, the transverse magnetic induction intensity decreases, the magnetic anisotropy is significant, and the iron loss decreases.

This study investigated the effects of uniaxial tensile strain on the magnetization process of an Fe-9wt%Ni (9Ni) alloy to increase understanding of its magnetic behavior. As the applied strain was increased from 0 to 14 %, the magnetization curve changed remarkably, particularly under a high-intensity magnetic field, and magnetic flux density, relative permeability, remanence, and coercive force degraded significantly, especially at strains greater than the upper yield point. Increase in tensile strain caused increase in hysteresis losses, primarily because strain induced crystal defects, which affected the rearrangement of magnetic domains. Increased dislocation density was the primary contributor to the observed deterioration in magnetic properties; changes in texture and phase had little influence. This finding indicates that strain-induced deformation strongly affects the magnetic behavior of 9Ni alloys; this insight will be useful in research aimed at mitigating welding defects such as arc blow, that are attributed to the magnetization of Ni steel.

Two tetranuclear Co(II) complexes, [Co4(pmab)4Cl4] (1) and [Co4(pmab)4(OBz)2]Cl2 (2) [Hpmab = 2-{(p-pyridinylmethylene)amino}benzenemethanol], have been synthesized and characterized through single-crystal X-ray diffraction, IR and UV-VIS spectroscopy, and magnetic measurements. Structural analysis revealed that both complexes possess a [Co4O4] cubane-like metal core connected by μ3-alkoxo bridges. Magnetic measurements of Complex 1 indicate weak ferromagnetic interactions (J ~ +0.75 cm−1) within the tetranuclear core, while Complex 2 exhibits antiferromagnetic behavior due to the presence of syn-syn bridging benzoate ligands. Alternating current (AC) magnetic measurements suggest that Complex 1 exhibits slow magnetic relaxation behavior.