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The design and synthesis of efficient adsorbents for the recovery of precious metals from secondary resources are of great environmental and economic significance. Herein, a magnetic sulfur‐doped composite CoFe2O4@S–CoWO4 (CF@S–CoWO4) is developed through a hydrothermal synthesis method, which is used to selectively recover gold in aqueous media. Significantly, CF@S–CoWO4 exhibits the best overall performance with gold ions adsorption capacity (Qmax) and distribution coefficient (Kd) are 1049 mg g−1 and 4.4 × 106 mL g−1, respectively, which are much higher than those of other gold adsorption materials. The selectivity coefficients (K) toward other metal ions (Pd2+, Ca2+, Mg2+, Cd2+, Al3+, Li+, Ni+) are also higher, which suggests that CF@S–CoWO4 had a preferential selectivity for Au3+ in coexisting ion solutions. Moreover, the antianion interference of the composite follows the order: SO42− > PO43− > NO3− > CO32−, and it also shows very good reusability with adsorption efficiency at 81.78% after four repeated cycles. Based on characterizations and calculation, it is found that Au(III) mainly undergoes chelation and reduction reactions in the S sites in CF@S–CoWO4, which indicates the important role of S sites. Hence the CF@S–CoWO4 composite demonstrates a promising application for the recycling of gold ions from electronic wastewater. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles with the size of 218, 73, and 50 nm were added to Ni-P electroless coating to create NiO@Ni-P nanoparticle reinforced composite coating on a brass substrate. The nanoparticles were synthesized by the green synthesis method, using Artemisia dracunculus extract. The coatings had amorphous structure and nodular morphology. The results of Tafel and EIS tests showed that the coating containing nickel oxide nanoparticles with an average size of 73 nm, had the highest corrosion resistance. The results of the tribocorrosion test under open circuit potential condition revealed Ni-P-(73 nm)NiO coating had the highest tribocorrosion resistance. Heat treatment at 400°C caused considerable improvement in the saturation and remnant magnetization of the composite coating, the value of saturation and remnant magnetization increased from 5 and 0.1 emu/g for simple Ni-P coating to 12 and 2 emu/g for NiO@Ni-P coating respectively, and the coercive field of the samples also enhanced. [ABSTRACT FROM AUTHOR]

Bi4Ti3O12-BaTiO3 (BTO-BT) nanocomposite, a Aurivillius oxide, which is synthesised by modified solid-state route, and characterised by various techniques like FTIR, XRD, TEM, UV-DRS, Zetasizer Nano-ZS, AFM, BET, SEM-EDX and XPS for the phase identification, microstructural analysis, bandgap determination, elemental analysis and oxidation state of the material. Formation of BTO-BT nanocomposite (orthorhombic and cubic) confirmed by Le-Bail fitting analysis with the help of XRD data. The electrical measurement of the material showed the existence of semiconducting grains and insulating grain boundaries responsible for Maxwell relaxation and a high dielectric constant of value 4.75 × 103 at 368 K was observed. The Magnetic behaviour studied by SQUID indicates it to be magnetically frustrated materials. The material was found to be applicable in photocatalytic degradation of Rhodamine B under UV light through major reactive species, i.e. OH. radicals and O2.- generated during the photocatalytic reaction proved to be following the first-order kinetics. [ABSTRACT FROM AUTHOR]

Saturation and cross‐coupling effects have a significant impact on the magnetic behaviour of a permanent magnet synchronous motor (PMSM), which cannot be analysed by the conventional linear model in the direct and the quadrature axis. This study introduces a precise two‐axis flux linkage model for PMSMs to offer a better depiction of the relationship between the flux linkages and corresponding currents. A parameter determination methodology is developed to identify the model parameters for a PMSM, and based on these works; the condition of a PMSM can be estimated. The process requires no geometrical parameter of the machine and little computational effort. Once the model parameters are determined, the torque estimation of a PMSM is simple enough to be made in real‐time in a motor drive controller. Finite‐element analysis and experimental results demonstrate the feasibility and accuracy of the improved model. It follows that the proposed non‐linear PMSM model based on current injection and bivariate function approximation can significantly enhance modelling precision of flux linkage and inductance over the entire range of current excitation in the application of PMSM drive. [ABSTRACT FROM AUTHOR]

In2O3 is multifunctional material with rich physical phenomena. In this paper, effects of Fe and Cu doping on the physical properties of In1.95-xCr0.05MxO3 (M = Fe, Cu) thin films prepared by sol-gel method followed by spin-coating technique were investigated. The films were characterised using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectrophotometer, Hall effect, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer. Doping with Cu reduced the lattice parameter and optical transmittance of In1.95-xCr0.05MxO3 films more than that with Fe. In addition, Cu doping induced p-type conductivity in In1.95-xCr0.05MxO3 films. Optical band gap was increased from 3.76 eV for In1.95Cr0.05O3 to ~ 3.8 eV for both Cu- and Fe-doped films, which was attributed to quantum confinement behaviour. Average grain size measured using TEM was reduced from 8.2 nm for In1.95Cr0.05O3 to 6.6 and 5.6 nm for Fe and Cu doped films, respectively. Saturation magnetisation of films was reduced with Fe doping more than that with Cu doping. Magnetic behaviours of films were explained within the framework of bound magnetic polaron model. [ABSTRACT FROM AUTHOR]

Electrical steel shows a distinct non‐linear and anisotropic behaviour even for non‐oriented steel. The flux guidance in electrical machines is realised by ferromagnetic steel sheets, and therefore it is necessary to consider the anisotropy in the simulation to have reliable and accurate results. Due to the fact that the reduction of silicon steel waste in the production process of electrical machines is crucial, and to enhance the material utilisation the segmentation is employed in the construction of electrical machines. The segmentation further allows to enhance the magnetic behaviour of the machine by considering the easy magnetisation axis in the design process. Nowadays, consideration of ferromagnetic anisotropy in the simulation of electrical machines is not accurate. To cope with these inaccuracies, in this contribution, a vectorial anisotropy model based on two‐dimensional measurements is employed to the simulation of a segmented electrical machine, which is not state of the art in current machine computation. With the presented methodology, it is possible to simulate and design segmented electrical machines in an accurate fashion taking the ferromagnetic anisotropy into account. [ABSTRACT FROM AUTHOR]

Coated steel substrate by FeCo/Al 2 O 3 nanoparticle with various Co concentrations realized by a thermal spraying process, preliminary powder alloy was elaborated by mechanical alloying technique for 20 h of milling time. The aims of this work are to study the effect of thermal spraying process and mechanical alloying on chemical composition, magnetic behaviour, structure and mechanical properties of coating. After mechanical alloying, the crystallite sizes of the powder were decreased from 18 to 7 nm and the lattice strains increased from 0.36 to 0.56%. This is due to the phenomenon of diffusion of cobalt in the iron lattice and the milling effect. After thermal spraying, many different phases appeared in the coating, such as Al 2 FeO 4 , CoAl 2 O 4 , CoFe and CoFe 2 O 4 . Magnetic behaviour was influenced by this change in the chemical composition of coating. The maximum saturation magnetization was found in Fe 40 Co 20 (Al 2 O 3) 40 sprayed powder, however, the minimum coercivity was found in Fe 50 Co 10 (Al 2 O 3) 40 sprayed powder. Mechanical properties' parameters such as microhardeness and Young's modulus were enhanced by the change in chemical composition during mechanical alloying and thermal spraying process. [ABSTRACT FROM AUTHOR]

The dissolution of anhydrous iron bromide in a mixture of pyridine and acetonitrile, in the presence of an organic amine, results in the formation of an [Fe34] metal oxide molecule, structurally characterised by alternate layers of tetrahedral and octahedral FeIII ions connected by oxide and hydroxide ions. The outer shell of the complex is capped by a combination of pyridine molecules and bromide ions. Magnetic data, measured at temperatures as low as 0.4 K and fields up to 35 T, reveal competing antiferromagnetic exchange interactions; DFT calculations showing that the magnitudes of the coupling constants are highly dependent on both the Fe‐O‐Fe angles and Fe−O distances. The simplicity of the synthetic methodology, and the structural similarity between [Fe34], bulk iron oxides, previous FeIII–oxo cages, and polyoxometalates (POMs), hints that much larger molecular FeIII oxides can be made. [ABSTRACT FROM AUTHOR]

Novel nano composite (ALW/CoFe2O4) adsorbent was synthesized from Apocynaceae leaf waste activated carbon (ALW) in combination with CoFe2O4by an auto combustion method for the removal of Reactive Red 141 dye and microorganisms against S. aureus, E. coli and C.albicans. The synthesized nano composite ALW/CoFe2O4 was characterized by SEM, EDX, BET, XRD, FTIR, TG & DSC and VSM. The results from these analytical techniques confirmed the aggregation of CoFe2O4 nano particles on the surface of ALW and VSM study showed its magnetic behavior. Subsequently, ALW/CoFe2O4 was adopted in batch mode adsorption studies by varying pH, adsorbent dosage, concentration and temperature. The adsorption efficiency was investigated under optimum conditions such as pH(6.5), adsorbent dosage (50 mg), contact time (70 min). The feasibility of adsorption was analyzed by fitting the data with pseudo first order, pseudo second order, Langmuir isotherm and Freundlich isotherm. The results showed that pseudo second order kinetics and Langmuir isotherm equation favour the adsorption of RR 141 on ALW/CoFe2O4. According to the thermodynamic study, it was very effective at higher temperatures and the thermodynamic parameters ∆Go, ∆Ho and ∆So were also evaluated for this adsorption. Furthermore, the antimicrobial activity of ALW/CoFe2O4 was tested by well diffusion method and compared with standard antibiotic. This ALW/CoFe2O4 exhibit good antimicrobial action with the zone of inhibition in the range of 10-17 mm. The synthesized nano composite (ALW/CoFe2O4) was evaluated for antimicrobial activityagainst (Staphylococcus aureus, Escherichia coli and Candida ablicans),usingwell diffusion methodand compared with standard antibacterial (Streptomycin) and antifungal (Amphotericin B).The antibacterial activity of ALW/CoFe2O4 against S. aureus (range between from 11.83 ± 0.23 mm to 17.5 ± 0.16 mm) and (range between E. coli 10.5 ± 0.40 to 17.0 ± 0.41 mm), while antifungistatic effectagainst C. albicans(range between 11.0 ± 0.24 to 17.6 ± 0.08), with different concentrations (100-500 mg) From the obtained results the antimicrobial activity of synthesized ALW/CoFe2O4 more or less same in the range between 11 and 17.56 mm of zone of inhibition. [ABSTRACT FROM AUTHOR]

The full potential linearized augmented plane wave method of density functional theory has been used to investigate the structural, electronic, magnetic and thermoelectric properties of cubic perovskites BaVO and LaVO. The ferromagnetic ground state has been found to be stable by comparing the total energies of non-spin-polarized and spin-polarized calculations performed for optimized unit cells. For both compounds, the bond length and tolerance factor are also measured. From the band structures and density of states plots, it is found that both compounds are half-metallic. We found that the presence of V at the octahedral site of these perovskites develops exchange splitting through p-d hybridization, which results in a stable ferromagnetic state. The observed exchange splitting is further clarified from the magnetic moment, charge and spin of the anion and cations. Finally, we also presented the calculated thermoelectric properties of these materials, which show that half-metallic BaVO and LaVO materials are potential contenders for thermoelectric applications. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C5H7O2)2 (C6H12N2)]n, was obtained as a one-dimensional coordination polymer from bis(acetylacetonato)di-aquacobalt(II), [Co(acac)2 (OH2)2], and 1,4-diaza-bicyclo[2.2.2]octane (DABCO), a diamine with good bridging ability and rod-like spacer function. In the chain complex that extends along the c axis, the CoII atom is six-coordinated, the O-donor atoms of the chelating acac ligands occupying the equatorial positions and the bridging DABCO ligands being in trans-axial positions. In the crystal structure, the DABCO ligand is conformationally disordered in a 50:50 manner as a result of its location across a crystallographic mirror plane. The metal-metal distance is very close to that in a related compound exhibiting weak antiferromagnetic exchange between the CoII ions, and the title compound can thus be useful for obtaining more information about the contribution of different bridges to the magnetic coupling between paramagnetic ions. [ABSTRACT FROM AUTHOR]

CoFe/Si interfacial structures have been realised by electron beam evaporation of CoFe magnetic alloy on p- and n-Si substrates. These realised interfacial structures have been characterised from X-ray diffraction (XRD), atomic force microscopy (AFM), magnetic force microscopy (MFM) and magnetisation (M–H) characteristics. XRD data have shown the presence of CoFe (bcc phase) and β-FeSi2phases for CoFe/p-Si interfacial structures, whereas CoFe/n-Si interfacial structures have shown the presence of CoFe (bcc and fcc) phases along with Fe3Si, ϵ-FeSi and β-FeSi2silicide phases having nanodimension crystallites. TheM–Hcharacteristics have shown the superparamagnetic type behaviour for CoFe/p-Si structure, whereas CoFe/n-Si structure shows a feature of interfacial antiferromagnetic (AF) coupling. The observed magnetic behaviour has been understood due to the presence of various magnetic phases and their nanosized grains. The MFM data of domain size have also been correlated with the observed magnetic behaviour. CoFe/n-Si structures have shown a significant feature of giant magnetoresistance (GMR) as compared to CoFe/p-Si structures. It has been found that CoFe/p-Si structures show a distinctly different behaviour than CoFe/n-Si structures for their chemical structure, morphology and magnetic behaviour. [ABSTRACT FROM AUTHOR]

A dinuclear compound [Mn(L)( μ-tp)](PF)⋅3.57HO ( 1) [L = N,N-(bis(pyridin-2-yl)benzy-lidene)-1,3-propanediamine and tp = terephthalate dianion] has been isolated and characterized on the basis of microanalytical, spectroscopic and other physicochemical properties. X-ray structural study showed interesting bis(bidentate) bridging motif of tp in the dicationic dinuclear unit [Mn( μ-tp)]. Each manganese(II) centre adopts a rare distorted trigonal prismatic geometry with an MnN O chromophore. Chelation of the tetradentate Schiff base (L) along with bis(bidentate) bridging of two O atoms of tp complete hexacoordination around each manganese(II) centre. The dinuclear units of 1 are associated through cooperative C-HF hydrogen bonds and π π, C-H π and rare anion π interactions to promote the dimensionality in a graded manner. Variable temperature magnetic susceptibility measurement of 1 in the 2-300 K temperature range revealed weak anti-ferromagnetic interaction presumably due to long bridging arm of tp. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This paper describes a multidisciplinary study approach (petrography and rock magnetism) conducted on samples collected from the study area to characterise the magnetic mineralogy and to determine if the magnetisation of both lithologies were induced or retain a remnant component. Petrophysical, mineralogical and geochemical analyses confirm bimodal aspects, particularly in basic rocks; the two magnetic modes depend essentially on the mineralogical and geochemical characteristics of the samples. The ultramafic rocks comprise a highly altered primary mineralogy with chromite and magnetite as magnetic phases. The second type is of mafic composition with a less altered primary mineralogy and essentially magnetite and/or (hemo-ilmenite) as a carrier of magnetic mineralisation. Sulphides are characterised by high concentrations of Cu, Zn and Pb. The mineralogy is composed mainly of pyrrhotite (85% to 90%), sphalerite, galena, chalcopyrite, arsenopyrite and, occasionally, stannite. Monocline pyrrhotite seems to be the magnetic carrier of magnetisation in both Draa Sfar and Koudiat Aïcha. However, we suspect a different amount of hexagonal pyrrhotite as the cause of different magnetic behaviour. Paleomagnetic and thermomagnetic analyses reveal different. The calculated characteristic direction of natural remnant magnetisation for sulphides was used to model the magnetic anomaly of Draa Sfar. The proposed model match the geological features concluded from geological mapping and boreholes. Results from this work can be very useful for any modelling processes of magnetic anomalies suspected due to a sulphide mineralisation in an area with poor outcrops and no presence of boreholes information or of any geological or geochemical data. [ABSTRACT FROM AUTHOR]

The organic-inorganic coordination polymer of the general formula {[NiL][Co(NCS)]} (where L = 5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) has been synthesized and characterized by IR, UV-Vis, DSC/TG, DTA/TG/MS methods. The magnetic behaviour of this complex has also been investigated within the temperature range 1.8-300 K. The IR spectrum indicates the presence of bridging M-NCS-M′ ligands. The absorption bands of UV-Vis spectrum confirm that the coordination environment of nickel(II) ions changes from square planar for [NiL](ClO) to octahedral for {[NiL][Co(NCS)]}. The obtained compound is stable at room temperature, but within the range 246-282 °C decomposes in a three-stage process. The first step is associated with decomposition of the coordination polymer to the cationic [NiL] and anionic [Co(NCS)] units; the next two stages correspond to gradual decomposition of the macrocyclic ring. The value of molar magnetic susceptibility (χ T = 2.16 cm molK) indicates that the compound is paramagnetic. [ABSTRACT FROM AUTHOR]

A new iron(II) coordination polymer, [FeCl(NCH)(NCH)], has been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. This material crystallizes in the monoclinic space group C2/c, with a = 11.2850(6), b = 13.8925(7), c = 17.0988(9) Å and β = 94.300(3)º ( Z = 4). The crystal structure consists of neutral zig-zag chains, in which the iron(II) ions are octahedrally coordinated. The infinite polymer chains are packed into a three-dimensional structure through C-H···Cl interactions. Magnetic susceptibility measurements reveal the existence of weak antiferromagnetic interactions between the iron(II) ions. The effective magnetic moment, μ = 5.33 μ, is consistent with a high-spin iron(II) configuration. Graphical Abstract: The crystal structure of the coordination polymer [FeCl(NCH)(NCH)] consists of neutral zig-zag chains, in which the iron(II) ions are octahedrally coordinated.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Exchange bias and spin valve structures with Fe as ferromagnetic layers selectively enriched in 57Fe and Ir–Mn of different compositions as antiferromagnetic pinning layers have been prepared by r.f. sputtering. Conversion Electron Mössbauer Spectroscopy and Magneto Optic Kerr Effect have shown that the local structure and interactions in the whole ferromagnetic layers, with direct influence on their magnetic reversal processes, depend on growing order of the layers and composition of the AF layer. Interfacial atomic diffusion is the main reason of perturbing the local structure of the ferromagnet. Mössbauer Spectroscopy is a powerfool tool which allows a detailed analysis of local configurations, in order to optimize the magnetic and giant magnetoresistive parameters of such multilayers of important technological applications. [ABSTRACT FROM AUTHOR]

This review outlines the development of electroless Ni–P composite coatings. It highlights the method of formation, mechanism of particle incorporation, factors influencing particle incorporation, effect of particle incorporation on the structure, hardness, friction, wear and abrasion resistance, corrosion resistance, high temperature oxidation resistance of electroless Ni–P composite coatings as well as their applications. The improvement in surface properties offered by such composite coatings will have a significant impact on numerous industrial applications and in the future they will secure a more prominent place in the surface engineering of metals and alloys. [ABSTRACT FROM AUTHOR]

Soft magnetic nanocrystalline alloys have attracted great fundamental interest in recent years due to their two-phase structural and magnetic behaviour. We review first the reliability of the fitting procedures of spectra obtained by 57Fe Mössbauer spectrometry which is a very efficient tool to investigate such materials. Then, we report the common features which characterise the temperature dependence of Mössbauer spectra; the hyperfine field temperature dependence of both the crystalline grains and the intergranular phase is discussed for different crystalline fractions in order to model the magnetic behaviour of the nanocrystalline alloys. [ABSTRACT FROM AUTHOR]

This review outlines the development of electroless Ni-P composite coatings. It highlights the method of formation, mechanism of particle incorporation, factors influencing particle incorporation, effect of particle incorporation on the structure, hardness, friction, wear and abrasion resistance, corrosion resistance, high temperature oxidation resistance of electroless Ni-P composite coatings as well as their applications. The improvement in surface properties offered by such composite coatings will have a significant impact on numerous industrial applications and in the future they will secure a more prominent place in the surface engineering of metals and alloys. [ABSTRACT FROM AUTHOR]