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Highlights: [•] Magnetic interaction causes disturbance forces in a reticle stage. [•] These forces are position dependent and can be proportional to velocity as well. [•] Estimating the disturbance force is possible by tracing control-loop signals. [•] By two-directional motion the two disturbance types can be distinguished. [•] Using the estimates in compensation tables reduces the error from 5 to 1.8nm. [Copyright &y& Elsevier]

A self-assembly process in a magnetically aligned anisotropic conductive adhesive (MA-ACA) is a novel approach to selectively create high-density vertical interconnects by magnetic interaction between ferromagnetic input–output pads and particles. In order to characterize self-assembly vertical interconnects created in an MA-ACA, quad-flat no-lead chips with 40 daisy chain pads were assembled on a printed circuit board. In reliability tests, the dc resistance of self-assembly test samples was observed to be 35.9% and -12.1% changed at temperatures of 85 ^\circ\C and -\55\ ^\circ\C, respectively, after 700 thermal shock cycles and 0.4% changed after an 8-h vibration test. In contrast, the dc resistance was observed to be significantly 41.4 \Omega increased due to humidity absorption after an 85 ^\circ\C temperature–85% humidity test for 500 h. Thus, in order to prevent humidity percolation in the self-assembly vertical interconnects, a Parylene-C material was used as a barrier layer. The dc resistance change of Parylene-deposited test samples with a thickness of 10 \mu\m was observed to be greatly 85.2% reduced after an 85 ^\circ \C temperature–85% humidity test. In addition, based on a Weibull distribution model, the mean time to failure of self-assembly vertical interconnects was estimated to be importantly 94.7% improved. Consequently, the proposed self-assembly packaging using a Parylene material is applicable to cost-effective electronic applications. [ABSTRACT FROM PUBLISHER]

Different proportion Ce doping NiCuZn ferrite was synthesised by the sol–gel and self-propagating high temperature synthesis method. Through using the X-ray diffraction analysis on the sample, we can know that it is a typical spinel structure and the powder grain size is ∼30 nm. According to the Mössbauer spectrum measurement, absorption area and hyperfine field relatively reduce with increase in Ce3+ doping content, but B absorption area increases and hyperfine field has little change. Hysteresis loop shows coercivity Hc, and remanent magnetisation Mr increases with change of doping. It may be that the magnetic anisotropy constant changing with particle size and domain wall movement caused. [ABSTRACT FROM AUTHOR]

A different proportion of Co, Bi doping NiCuZn ferrite was synthesised by the sol–gel self-propagating high temperature synthesis method. X-ray diffraction analysis showed that the sample grain density increases with the increase in doping amount of Bi ion. The hysteresis loop at T = 300 K of the samples showed that this ferrite is typical ferrimagnetic, coercive force Hc increases with the increase in doped ion and the saturation magnetisation increases firstly and then decreases with the increase in doped ion. Through Mössbauer spectrum analysis, the absorption area of A site is relatively reduced and the absorption area of B site is relatively increased with the compound doped increase. [ABSTRACT FROM AUTHOR]

A 2-D grid copper(II) complex [Cu(μ3-H2dpzpda)(N3)]n(ClO4)n ( 2) has been synthesized and structurally characterized. The copper atom in the complex is six-coordinated in an octahedral geometry. The azide anions coordinated with copper in a 1-end form, and the perchlorate anions are not coordinated to copper centers. The structure shows an orthogonal overlap of orbitals through the bridging pyrazine. Extensive hydrogen bonds were observed in 2D networks. Magnetic studies indicate the presence of very weak antiferromagneic coupling between copper(II) ions. [ABSTRACT FROM AUTHOR]

Abstract: The last few years have seen a huge renaissance in the study of the magnetism of lanthanide coordination complexes, especially in the field of single molecule magnets (SMMs) due to the large inherent anisotropy of lanthanide metal ions. It has led to intense activity on the part of synthetic chemists to produce systems suitable for detailed study by physicists and materials scientists, thus synthetic development has been playing a major role in the advancement of this field. In this review, we demonstrate the research developed in the few years in the fascinating and challenging field of Dy-based SMMs with particular focus on how recent studies tend to address the issue of relaxation dynamics in these systems from synthetic point of view. In addition, the assembly of multinuclear Dy SMMs using various ligands is summarized, showing that several typical motifs are favorable structural units which could be exploited in the formation of new Dy-based SMMs and supramolecular architectures. [Copyright &y& Elsevier]

Abstract: The influence of a magnetic field on the microstructural evolution of nano-scale cobalt particles precipitated in a Cu–Co alloy during annealing at 973K has been investigated using transmission electron microscopy (TEM). TEM observations revealed that an external field of ∼0.9T accelerated precipitation and that the coherent–incoherent transition consequently occurred at an earlier time. The presence of the field, however, resulted in no significant change in the shape of the individual particles. A two-dimensional Monte Carlo simulation with the Ising spin model was also carried out to investigate the influence of an external magnetic field on the precipitation behaviour. These Monte Carlo simulations take both the chemical and magnetic interactions between solute atoms/clusters in the alloy into account, and successfully reproduced the qualitative features of the precipitation behaviour under a magnetic field seen in the experiments. [Copyright &y& Elsevier]

The magnetic interactions in the V2Cl [ABSTRACT FROM AUTHOR]

Abstract: One Cu(II) (1) and two Ni(II) (2,3) novel compounds based on triethanolamine have been obtained and characterized by elemental and spectral analyses. Single-crystal X-ray crystallography has revealed that the crystal structure of compound 1 results from co-crystallization of ionic dinuclear [Cu2 (H3L) 2Cl2 ]Cl2 (1a) and molecular tetranuclear [Cu4 (HL) 2Cl4 ] (1b) species in a 1:0.036 ratio, both possessing an atrane structure. The molecular structure of [Ni2 (H3L) 2Cl2 ]Cl2 (3) resembles the compound [Cu2 (H3L) 2Cl2 ]Cl2 (1a). In both centrosymmetric dinuclear complexes, each metal atom exhibits an octahedral Cl2NO3 coordination provided by a tetradentate non-deprotonated triethanolamine ligand and two bridging chloride anions. The compound [Ni(H3L) 2 ]Cl2 (2) has an ionic crystal structure, where triethanolamine acts as a non-deprotonated tridentate ligand, one of the OH-groups not being involved in coordination to the Ni atom. Analysis of the magnetic susceptibility results for compounds 1–3 reveals the presence of an antiferromagnetic interaction in the case of the Cu-based dimer 1 (J =−1.99(7)cm−1, g =2.07(9)) and a ferromagnetic interaction for the Ni-based dimer 3 (J =+7.17(3)cm−1, g =2.35(2)) with the ground state S =2. A significant zero field splitting (ZFS) effect was found for the Ni(II)-based complexes (D =−6.5cm−1, E =0.4cm−1). The thermal stability of the compounds was studied under a nitrogen atmosphere. The biocidal activities against some fungi (Aspergillus niger ATCC 53346, Penicillium frequentans ATCC 10110, Alternaria alternate ATCC 8741) and bacteria (Pseudomonas aeroginosa ATCC 27813 and Bacillus sp. ATCC 15970) were also evaluated. The moisture behavior of the obtained crystalline compounds was studied by dynamic water vapor sorption analysis. [Copyright &y& Elsevier]

The purpose of this paper is to presents a new type of dynamic balancing system, having a driving solution of the rotating part based on magnetic interactions. The magnetic system also plays the role of an elastic bearing. The structure has some important advantages: an easy to design and build mechanical system; no influence of the environmental factors on the measuring accuracy; low production costs; no direct transmission from the driving motor to the rotor that has to be balanced. In the first part of the article it is presented the technical solution which allows the dynamic balancing evaluation depending on the radial displacement between two disks with permanent magnets, creating a magnetic coupling. It was analytically calculated, using a 2D model, the torque given by the axial magnetic coupling and the resultant magnetic force whose value depends on the misalignment of the balanced part, against the equilibrium position. Due to the specific geometry, to validate the 2D analytical calculation model, it was necessary to create a FEM model of the magnetic system. A simulation was performed to evaluate the dependence between the radial displacements and the magnetic forces on the one hand and dependence of the torque versus angular displacement, on the other hand. It was used a 3D simulation software, specific for these kind of problems - the INFOLYTICA software. To validate both the 2D the analytical calculation and 3D simulation model some measurements were made on a test stand, both to measure the resultant magnetic force, proportional to the centrifugal force created by the unbalance D, and to measure the torque value due to angular displacement. The final results show that there is a similarity between 2D analytical calculation model, 3D simulation and practical measurements.. [ABSTRACT FROM AUTHOR]

Abstract: CoHo x Fe2−x O4 ferrites (x=0.00–0.1) were prepared by the co-precipitation technique and the effect of holmium substitution on the magnetic properties was investigated. X-ray diffraction reveals that the substituted samples show a second phase of HoFeO3 along with the spinel phase. The magnetic properties such as the saturation magnetization (M s ), coercivity (H c ) and remanence (M r ) are obtained from the hysteresis loops. It is observed that the M s decreases while H c increases with Ho3+ substitution. The decrease of saturation magnetization is attributed to the weakening of exchange interactions. The coercivity increases with increase of the Ho3+ concentration, which is attributed to the presence of an ultra-thin layer at the grain boundaries that impedes the domain wall motion. Low field AC susceptibility was also measured over the temperature range 300–600K at the frequency of 200Hz. It decreases with the increase of temperature following the Curie–Weiss law up to the Curie temperature. Above the Curie temperature it shows paramagnetic behavior. The increase in coercivity suggests that the material can be used for applications in perpendicular recording media. [Copyright &y& Elsevier]

Damping properties of a damper utilizing magnetic particles are investigated experimentally. A group of magnetic particles is treated as the working fluid in a damper instead of oil. In the presence of magnetic field, the damping force of the particles damper drastically increases. The maximum damping force appears near the dead center of vibration and higher frequency produces stronger maximum damping force, when the vibration frequency is in the range of low frequency below 5 Hz. [ABSTRACT FROM AUTHOR]

An iron ball floats in midair in a plastic tube when the plastic tube is coaxially inserted in a ring-shaped permanent magnet. A ring permanent magnet has a special paraboloidal interface around its axis, the magnetic field Bz is of negative value, and points down in the range Zlow. But it is of positive value and points up in the range Zup; it is 0 at Z0 position. The iron ball cannot be stable levitated over the ring magnet no matter it is in the Zlow or Zup regions; it is only possible to realize the stable levitation of the iron ball at Z0 position. Theoretical calculation and experiment have been done and identified the stable levitation of an iron ball over a ring magnet. It is helpful to design and develop new magnetic levitation system for practical applications. [ABSTRACT FROM AUTHOR]

Abstract: Cu(II) complexes of the tridentate thiosemicarbazone ligands diacetyl monooxime thiosemicarbazone (dmoTSCH2 ) and diacetyl monooxime (4-phenyl)thiosemicarbazone (dmoPhTSCH2 ) have been synthesized. X-ray crystal structures of dmoPhTSCH2 and [Cu(dmoTSCH)Cl]2 ·H2O (1·H2O) are also reported. The Cu(II) compound 1·H2O is a dinuclear complex, where the Cu(II) centers have a square pyramidal geometry and are bridged by two thiolato ligands. A C2 axis passes through the middle of Cu2S2 rectangle. Variable temperature susceptibility measurement for 1·H2O shows that this compound exhibits a very weak antiferromagnetic behavior (in the solid state) with J 1 = −2.97cm−1, using the Heisenberg isotropic spin Hamiltonian (H =−J 1 S 1·S 2). DFT calculations show that the intramolecular magnetic interaction should be ferromagnetic, and the net antiferromagnetic behavior is due to competition with antiferromagnetic intermolecular interactions through hydrogen bonds. [Copyright &y& Elsevier]

Abstract: The rare earth-iron oxalate-bridged complexes CeFe(C2O4)3·9H2O and PrFe(C2O4)3·9H2O have been synthesized. In the sample CeFe(C2O4)3·9H2O, the magnetic susceptibilities of the compound can be fit to the Curie-Weiss law and Weiss paramagnetic Curie temperature of θ=-1.4K.the hyperfine field parameters show that the dependent of the hyperfine field and the spontaneous magnetization and that of the spontaneous magnetization and temperature in the latticed FeII and FeIII.There are a clear bifurcation phenomenon of the field-cooled (MFC) and Zero-field-cooled (MZFC) magnetization curves at the Néel temperature (4K).In the sample PrFe(C2O4)3·9H2O,the Weiss paramagnetic Curie temperature θ=-2.7K,There are a bifurcation of the ZFC and FC plots at the Néel temperature (6K).The negative Weiss constant indicates an intramolecular antiferromagnetic coupling interaction between the adjacent Fe(II) and Fe(III) ions through the oxalate bridge.The oxalate group has been shown to be an excellent bridging ligand in supporting the magnetic exchange interaction. [Copyright &y& Elsevier]

Abstract: The effects of grinding on interparticle magnetic interactions for an ensemble of agglomerated MnFe2O4 nanoparticles have been studied. Structural analyses showed that by grinding the samples, a small variation in size of crystallites and lattice strain will occur. ac Magnetic susceptibility measurements under different conditions and spin dynamics analysis suggest that freezing temperature is frequency dependent and it is in good agreement with critical slowing down model. This is an indication that these nanoparticles have superspin glass behavior. The estimated zυ and τ 0 parameters using critical slowing down model show that by increasing the grinding time the interaction between nanoparticles decreases. ac Susceptibility measurements in cooling and heating process show a thermal hysteresis. The thermal hysteresis decreased by increasing the grinding time. Also, the thermal hysteresis is frequency dependent and it increased as frequency decreased. These results showed that interparticle interactions such as dipole–dipole and exchange interactions between nanoparticles become weaker by grinding. [Copyright &y& Elsevier]

Abstract: This paper presents the design and implementation of a MIniature SwitchAble (MISA) connection system for stochastic modular robots. The MISA connector consists of attaching, aligning, locking, detaching and holding mechanisms. The connection function can be switched on and off by controlling shape memory alloy (SMA) actuators. Furthermore, it possess functions of self-attachment and self-alignment through magnetic interaction under random collision condition. The design details and prototype construction are presented. The preliminary experiments and results demonstrate feasibility and performance of this miniature connector. The potential application is to integrate it into modular microrobots. [Copyright &y& Elsevier]

Abstract: The intra- and the inter-chain magnetic interactions in [Ni(chxn)2Br]Br2, which is one of the typical one-dimensional (1-D) MX complexes are examined by using an unrestricted hybrid DFT (UB3LYP) method. Calculated effective exchange integral (J) value along the 1-D chain is 2J Intra =−4016K and is close to an experimental result (−3600K). On the other hand, a very weak anti-ferromagnetic inter-chain interaction through Br− ions is observed. The value is estimated to be 2J Inter =−2 to −6K. In addition to the J values, transfer integral (t), on-site Coulomb repulsion (U) and charge transfer energy (E CT) values along the 1-D chain are also estimated to be 0.46, 2.46 and 0.6eV, respectively. [Copyright &y& Elsevier]

Abstract: A new three-dimensional diamagnetic metal nitronyl nitroxide radical coordination polymer with an aqua cadmium cyanide framework Cd(NIT4py)(H2O)Cd(CN)4·H2O 1, was synthesized. X-ray crystallography reveals that the structure consists of 3D aqua cadmium cyanide built up by octahedral CdII coordinating to NIT4py and tetrahedral CdII (CN)4 units. Magnetic measurements show that the χ m T values are nearly constant at higher temperature. The lower χ m T values at lower temperature are related to intermolecular antiferromagnetic interactions of the radicals, which arise due to the hydrogen bonded network (T N =21K). [Copyright &y& Elsevier]

Abstract: The local structure distortion and the spin Hamiltonian (SH) parameters, including the zero-field splitting (ZFS) parameter D and the Zeeman g-factors g ‖ and g ⊥, are theoretically investigated by means of complete diagonalization method (CDM) and the microscopic spin Hamiltonian theory for tetragonal charge compensation CrF5O defect center in Cr3+:KMgF3 crystals. The superposition model (SPM) calculations are carried out to provide the crystal field (CF) parameters. This investigation reveals that the replacement of O2− for F− and its induced lattice relaxation Δ1(O2−) combined with an inward relaxation of the nearest five fluorine Δ2(F−) give rise to a strong tetragonal crystal field, which in turn results in the large ZFS and large anisotropic g-factor Δg. The experimental SH parameters D and Δg can be reproduced well by assuming that O2− moves towards the central ion Cr3+ by Δ1(O2−)=0.172R0 and the five F− ions towards the central ion Cr3+ by Δ2(F−)=0.022R 0. Our approach takes into account the spin–orbit (SO) interaction as well as the spin–spin (SS), spin–other-orbit (SOO), and orbit–orbit (OO) interactions omitted in previous studies. This shows that although the SO interaction is the most important one, the contributions to the SH parameters from other three magnetic interactions are appreciable and should not be omitted, especially for the ZFS parameter D. [Copyright &y& Elsevier]

Abstract: The effect of Cr doping on magnetic and electrical properties in the bilayer manganites La1.4Sr1.6(Mn1−y Cr y )2O7 (y=0–0.1) has been investigated. When y≤0.025, Cr doping enhances the three-dimensional magnetic transition temperature T C and the insulator–metal transition temperature T IM as well as decreases the peak resistivity at T IM, and the saturated magnetization decreases slightly. When y≥0.035, T IM decreases gradually accompanied by the increase of peak resistivity, but T C remains nearly constant, and the saturated magnetization decreases heavily. In the whole doping region, the two-dimensional magnetic transition temperature T ⁎ monotonously decreases with an increasing of Cr doping level. These results can be explained by considering different magnetic (including ferromagnetic and antiferromagnetic) interactions between Mn ions and Cr ions. [Copyright &y& Elsevier]

Abstract: The crystal field effect and microscopic origins of the Zeeman g-factors g // and g ⊥ for 6S(3d5) state ions at tetragonal symmetry crystal filed, taking into account the spin–spin (SS), the spin–other–orbit (SOO), and the orbit–orbit (OO) magnetic interactions besides the well-known spin–orbit (SO) magnetic interaction, have been investigated using the microscopic spin Hamiltonian theory and the complete diagonalization method (CDM). It is found that the g //(±1/2)≠ g //(±5/2) and g ⊥(±1/2)≠ g ⊥(±5/2), where the g-factors g //(±1/2) and g ⊥(±1/2) express the g-factors of the ground state , whereas the g-factors g //(±5/2) and g ⊥(±5/2) express the g-factors of the ground state . It is shown that although the SO magnetic interaction is the most important one, the contributions to the shifts of g-factors Δg //(=2.0023− g //) and Δg ⊥(=2.0023− g ⊥) from other three magnetic interactions including the SS, SOO, and OO magnetic interactions are appreciable and should not be omitted, especially for the shifts of g-factors Δg //(±5/2) and Δg ⊥(±5/2). The individual contributions to the shifts of g-factors arising from the spin quartet states and spin doublet states have been studied. The investigations show that the Δg //(±1/2) and Δg ⊥(±1/2) primarily result from the spin quartet states, whereas Δg //(±5/2) and Δg ⊥(±5/2) from the spin quartet states as well as the combined effects between the spin quartet states and the spin doublet states. The contribution to the shifts of g-factors from the net spin doublet states is zero. [Copyright &y& Elsevier]

Single-phase HoCrO3 samples were prepared using the conventional solid-state reaction. The temperature dependence of dc magnetic properties show that the ZFC and FC magnetization curves are irreversible strongly and nearly symmetrical below 141.0 K under 100 Oe. Moreover, there appears a novel magnetization behavior with negative magnetization (diamagnetism-like) characteristics. This behavior exhibits the coexistence of canted antiferromagnetic and weak ferromagnetic phase and the existence of competition mechanism below Tc1 = 141.0 K. In addition, it is also proved that Ho ion ordered weak CAFM below 7.5 K. The current novel magnetization can be interpreted from the interaction between paramagnetic Ho3+ moments and canted Cr3+ moments. [ABSTRACT FROM AUTHOR]

Abstract: Magnetostatic attraction may lead to formation of aggregates in stable colloidal magnetic suspensions and magneto-rheological suspensions. The aggregation problem of magnetic composites under differential sedimentation is a key problem in the control of the instability of non-Brownian suspensions. Against these attractive forces are the electrostatic repulsion and the hydrodynamic interactions acting as stabilizing effects to the suspension. This work concerns an investigation of the pairwise interaction of magnetic particles in a dilute sedimenting suspension. We focus attention on suspensions where the Péclet number is large (negligible Brownian motion) and where the Reynolds number (negligible inertia) is small. The suspension is composed of magnetic micro-spheres of different radius and density immersed in a Newtonian fluid moving under the action of gravity. The theoretical calculations are based on direct computations of the hydrodynamic and the magnetic interactions among the rigid spheres in the regime of low particle Reynolds number. From the limiting trajectory in which aggregation occurs, we calculate the collision efficiency, representing the dimensionless rate at which aggregates are formed. The numerical results show clear evidence that the hydrodynamic interactions are of fundamental relevance in the process of magnetic particle aggregation. We compare the stabilizing effects between electrostatic repulsion and hydrodynamic interactions. [ABSTRACT FROM AUTHOR]

Abstract: Magnetite nanoparticles, which are coated with oleic acid in a hexane solution and exhibit an average diameter of 7.7nm, were embedded in a porous silicon (PS) matrix by immersion under defined parameters (e.g. concentration, temperature, time). The porous silicon matrix is prepared by anodization of a highly n-doped silicon wafer in an aqueous HF-solution. Magnetic characterization of the samples has been performed by SQUID-magnetometry. The superparamagnetic behaviour of the magnetite nanoparticles is represented by temperature-dependent magnetization measurements. Zero field (ZFC)/field cooled (FC) experiments indicate magnetic interactions between the particles. For the infiltration into the PS-templates different concentrations of the magnetite nanoparticles are used and magnetization measurements are performed in respect with magnetic interactions between the particles. The achieved porous silicon/magnetite specimens are not only interesting due to their transition between superparamagnetic and ferromagnetic behaviour, and thus for magnetic applications but also because of the non-toxicity of both materials giving the opportunity to employ the system in medical applications as drug delivery or in medical diagnostics. [Copyright &y& Elsevier]

Abstract: Polycrystalline EuZrO3 has been synthesized by the solid-state reaction between EuO and ZrO2, and its structural and magnetic properties have been investigated. Rietveld analysis of the X-ray diffraction pattern indicates that EuZrO3 crystallizes in an orthorhombic perovskite structure. 151Eu Mössbauer effect measurement reveals that almost all the europium ions are present as the divalent state and occupy distorted sites with non-axial electric field gradients, in agreement with the orthorhombic structure. In contrast to previous reports, an antiferromagnetic transition was observed around 4.1K. The magnetic structure below the Néel temperature has been discussed. [Copyright &y& Elsevier]

Abstract: Microstructure, magnetic and optical properties of polycrystalline Fe-doped ZnO films fabricated by cosputtering with different Fe atomic fractions (x Fe) have been examined systematically. Fe addition could affect the growth of ZnO grains and surface morphology of the films. As x Fe is larger than 7.0%, ZnFe2O4 grains appear in the films. All the films are ferromagnetic. The ferromagnetism comes from the ferromagnetic interaction activated by defects between the Fe ions that replace Zn ions. The average moment per Fe ion reaches a maximum value of 1.61μB at x Fe =4.8%. With further increase in x Fe, the average moment per Fe ion decreases because the antiferromagnetic energy is lower than the ferromagnetic one due to the reduced distance between the adjacent Fe ions. The optical band gap value decreases from 3.245 to 3.010eV as x Fe increases from 0% to 10%. Photoluminescence spectra analyses indicate that many defects that affect the optical and magnetic properties exist in the films. [Copyright &y& Elsevier]

Abstract: The relations between the spin Hamiltonian (SH) parameters and crystal structure of Cr4+:α-Al2O3 crystals have been established. On the basis of this, the SH parameters including zero-field splitting parameter D and Zeeman g-factors (g || and g ⊥) for Cr4+ ions in Cr4+:α-Al2O3 crystals, taking into account the spin–spin (SS), spin-other-orbit (SOO) and orbit–orbit (OO) magnetic interactions in addition to the spin–orbit (SO) magnetic interaction, are theoretically investigated using complete diagonalization method (CDM). The theoretical results are in excellent agreement with the experimental ones when the upper three O2− ions rotate 0.94° toward [111] axis and the lower three O2− ions rotate 0.92° toward it. Hence, the local structure distortion effect plays an important role in explaining the spectroscopic properties of Cr4+ ions in Cr4+:α-Al2O3 crystals. This study shows that for Cr4+:α-Al2O3 the contributions arising from SS, SOO, and OO interactions to the zero-field splitting (ZFS) parameter D are appreciable, whereas those to g || and g ⊥ are quite small. [Copyright &y& Elsevier]

Abstract: We report a new synthesis route for preparation of single-domain barium hexaferrite (BaFe12O19) particles with high saturation magnetization. Nitric acid, known as a good oxidizer, is used as a mixing medium during the synthesis. It is shown that formation of BaFe12O19 phase starts at 800°C, which is considerably lower than the typical ceramic process and develops with increasing temperature. Both magnetization measurements and scanning electron microscope micrographs reveal that the particles are single domain up to 1000°C at which the highest coercive field of 3.6kOe was obtained. The best saturation magnetization of ≈60emu/g at 1.5T was achieved by sintering for 2h at 1200°C. Annealing at temperatures higher than 1000°C increased the saturation magnetization, on the other hand, decreased the coercive field which was due to the formation of multi-domain particles with larger grain sizes. It is shown that the best sintering to obtain fine particles of BaFe12O19 occurs at temperatures 900–1000°C. Finally, magnetic interactions between the hard BaFe12O19 phase and impurity phases were investigated using the Stoner–Wohlfarth model. [Copyright &y& Elsevier]

Magnetic interaction was included in the simulation of the evolution of the electron wave-packet of the hydrogen molecular ion H2+ in femtosecond intense pulsed laser fields applied along the molecular axis. This evolution was followed by solving 2-D time-dependent Schrödinger equation at some fixed inter-nuclear separations. Magnetic interaction effects at non-relativistic intensities induced a phase shift in the time evolution of the electron wave-packet, and an excess z-component angular momentum as compared with the results obtained in the absence of magnetic interaction. Furthermore, the H2+ electron WP displacement showed a drift and wiggling in the propagation direction which was different from that observed under pure electric field of the laser pulse. The local fluxes at different points of the 2-D space borders and the time-dependent induced angular momentum are calculated and analyzed. [ABSTRACT FROM AUTHOR]

Abstract: Hybrid density functional theory (HDFT) calculations have been carried out for clusters of p-NPNN extracted from the experimental crystal structures of the α-, β-, γ- and δ-phases in order to investigate the weak magnetic interactions between the organic radicals theoretically. From the systematic HDFT calculations for β- and γ-phase p-NPNN clusters, it was found that the magnetic long-range ferromagnetic and antiferromagnetic orderings would be presented in the β- and γ-phase p-NPNN crystals, respectively. [Copyright &y& Elsevier]

Abstract: We successfully isolated a new paramagnetic bidentate ligand tert-butyl 5-methoxy-2-pyridyl nitroxide (meopyNO). Complexation of nickel(II) and copper(II) perchlorates with meopyNO gave the corresponding ML2-type bis-chelated compounds. The magnetic studies showed that they were ground high-spin molecules with 2J/k B =+288(5) and +178(3)K for [M(meopyNO)2(H2O)2]·(ClO4)2 (M=Ni and Cu, respectively), where the spin Hamiltonian is defined as H =−2J(S 1 · S 2 + S 2 · S 3). From the crystallographic analysis, the torsion angles (ϕ) around M–O–N–C2py were 4.2(3)° and 6.87(19)°, respectively, being so small that the orthogonality between the magnetic radical π∗ and the metal dσ orbitals would be guaranteed. [Copyright &y& Elsevier]

Abstract: Hybrid DFT (HDFT) calculations were carried out for model clusters of paranitrophenyl nitronyl nitroxide (p-NPNN) whose geometrical structures were based on its β-phase crystal structure. The effective exchange integrals between the neighboring p-NPNN molecules were calculated for the qualitative understanding of the pressure-induced transition form ferro- to antiferro-magnetic state. In the high pressure-induced condition, it could be presumed that the p-NPNN molecules in the crystal was gradually shifted along several lines or was rotated around appropriate axes. From these model calculations, it was found that the ferromagnetic exchange interaction between the neighboring dimers changed to antiferromagnetic one by the structure deformations. [Copyright &y& Elsevier]

Abstract: Electronic structures, CDW/CP stability and magnetic properties of K4[Pt2(pop)4X]·2H2O (X=Cl, Br) complexes are examined by unrestricted DFT (UB3LYP) method. The calculated energies indicate that the CDW is a ground state, and energy differences between CDW and CP structures (Δ CP–CDW) are 0.34eV and 0.23eV for Cl and Br complexes, respectively, within the calculated models. Magnetic interactions between units in the CP structure are also calculated. Calculated intra-chain exchange coupling constants (J) are −889cm−1 and −1537cm−1 for Cl and Br complexes, respectively, indicating a strong anti-ferromagnetic interaction. On the other hand, calculated inter-chain J values suggest a negligible exchange interaction between two chains. In addition, it is also found that orbitals of potassium ions scarcely affect to Δ CP–CDW and J values. [Copyright &y& Elsevier]

Abstract: Thin ferromagnetic films with in-plane magnetic anisotropy are promising materials for obtaining high microwave permeability. To produce a bulk massive sample from thin films, multi-layer films made of a number of many thin films may be used. The paper reports on an experimental study of microwave and static magnetic properties of multi-layer iron-based films and composite samples made of these. The multi-layer films under study are deposited onto a mylar substrate by a magnetron-sputtering process performed in Ar atmosphere with controlled N2 admixture. The sputtered iron layers are alternated with SiO2 layers. The measured static and microwave magnetic properties of the bulk sample are found to differ from the properties of constituent films. This is an evidence for strong interactions between the magnetic layers in the sample, which interact at distances exceeding greatly the distance between adjacent magnetic layers. A theoretic model is developed to account for magneto-dipole interactions between iron films in a multi-layer system. The model explains the anomalously high demagnetization field of the sample observed in the measurements. [Copyright &y& Elsevier]

Abstract: In this work we report on swift heavy ion irradiation induced nano granular magnetic metallic Fe5Si3 silicide phase formation due to strong interfacial intermixing in Fe/Si bilayer samples. The bilayer samples have been irradiated with swift (100MeV) heavy (56Fe7+) ions having a fluence of 1×1014 ionscm−2. It has been found that swift heavy ion causes strong irradiation induced interfacial intermixing and forms nano granular magnetic metallic Fe5Si3 silicide in Fe/Si bilayer samples, which shows strong uniform magnetic interaction and interacting magnetic particle behaviour at room temperature (RT). [Copyright &y& Elsevier]

A new 1D azido and alkoxido-bridged Cu(II) coordination polymer, [Cu 2 (H 3 L)(μ-H 2 L)(μ-N 3)] n (1), was synthesized from the reaction of H 4 L, Cu(NO 3) 2 ·3H 2 O and NaN 3 in methanol, where H 4 L is (E)-2-((5-bromo-2-hydroxybenzylidene)amino)-2-(hydroxymethyl)propane-1,3-diol. Compound 1 was characterized by elemental analysis, spectroscopic methods and single-crystal X-ray diffraction. Both spectroscopic and structural studies confirmed the presence of the Schiff base and the azide ligands. Azido and alkoxido bridges connect two Cu(II) ions with different coordination environments. The Schiff base ligand, H 4 L, shows two coordination modes acting as H 3 L− and H 2 L2− to the metal cores. The azido ligands show both end-on and end-to-end bridging modes. The magnetic study performed in the 1.8–300 ​K range shows an overall ferromagnetic interaction among the copper(II) ions dominated by the coupling through the alkoxido bridge. We have calculated the value of the magnetic coupling constants by means of DFT calculations, and we compared their values with those obtained from the magnetic susceptibility measurements. Synthesis, crystal structure and magnetic interactions of a 1D Cu(II) coordination polymer was experimentally and theoretically investigated. [Display omitted] • Synthesis and crystal structure of a new alkoxido and azido bridged Cu(II) coordination polymer are reported. • Spectroscopic properties of a new 1D coordination polymer are investigated. • Magnetic interactions of a 1D Cu(II) coordination polymer was experimentally and theoretically investigated. [ABSTRACT FROM AUTHOR]

Abstract: The electronic and magnetic structures of monoclinic LiMnO2 are investigated by first-principles calculations with spin-polarized generalized gradient approximation. It is found that the Mn3+ ion is in the high-spin state. The ground state is found to be an insulating state with competing ferromagnetic and antiferromagnetic interaction, and it is this competition that results in the spin-glass behavior observed in monoclinic LiMnO2. [Copyright &y& Elsevier]

A new magnetically assisted transferred plasma torch (MA-TPT) was specially developed for the treatment of ceramic clay and harmful substances. The electrical plasma source consists mainly of a power buck converter and an alternating magnetic field, which allow sustaining a highly efficient plasma discharge at different arc lengths. The interaction of the electric arc with the magnetic field produces a broadening arc effect on the anode, enhancing the heat fluxes to the ceramic clay. Electrical and thermal characterization of the plasma torch showed that high thermal efficiency is easily reached with the current plasma con- figuration. In turn, the characterization tests of the vitrified clay revealed that the final vitrified product presents good chemical stability. [ABSTRACT FROM AUTHOR]

The radical harvesting state of a ribonucleotide reductase R2 subunit (RNR-R2) is theoretically investigated at the broken-symmetry DFT level. Recently, a high-resolution X-ray crystallography revealed a precise location of the active site structure of RNR-R2 (Class 1b) from C. ammoniagenes, and found a linking water near the tyrosine (Tyr) radical site. In this study, the magnetic interaction between the Tyr radical and the diiron core JTyr&bond;Fe is investigated for the first time. Used theoretical model for the active site is composed of diiron core, the Tyr residue, and surrounding side-chain groups. After the geometrical structure optimization of the core structures, the magnetic interaction between the iron centers was calculated to be JFe&bond;Fe = -77.82 cm-1, which was comparable to the experimental result of JFe&bond;Fe = -84 cm-1. The natural orbital analysis clearly showed that the magnetic interaction between the two iron centers mainly interact through the p orbital of the bridging μ-oxo. It was also calculated that the JTyr&bond;Fe interaction is negligibly weak, and the Tyr radical is almost in an isolated or a free radical state. These results suggest that the linking water may be used for (1) a confinement of the reactive Tyr radical in the hydrogen bonds or (2) a hydrogen-transfer coupled with electron transfer at the radical formation step of the Tyr. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

Abstract: FeCo-based nanostructured powders were prepared by mechanical alloying and subsequently heat treated in an attempt to optimize their magnetic properties. Although the annealed powders had grain sizes smaller than the magnetic exchange length, a low coercivity, H C, as expected from Herzer''s model, did not occur. All the possible causes for the larger than expected H C were analyzed. The magnetic measurements on the dilute and concentrated powder samples, as well as the temperature dependence of the magnetic properties from 10 to 300K, indicate that the degree of magnetic interaction between the individual powder particles, along with the particle morphology and size, causes the relatively high H C of 10–20Oe at room temperature. [Copyright &y& Elsevier]

With various low-temperature experiments performed on magnetic mineral extracts of marine sedimentary deposits from the Argentine continental slope near the Rio de la Plata estuary, a so far unreported style of partial magnetic self-reversal has been detected. In these sediments the sulphate–methane transition (SMT) zone is situated at depths between 4 and 8 m, where reductive diagenesis severely alters the magnetic mineral assemblage. Throughout the sediment column magnetite and ilmenite are present together with titanomagnetite and titanohematite of varying compositions. In the SMT zone (titano−)magnetite only occurs as inclusions in a siliceous matrix and as intergrowths with lamellar ilmenite and titanium-rich titanohematite, originating from high temperature deuteric oxidation within the volcanic host rocks. These abundant structures were visualized by scanning electron microscopy and analysed by energy dispersive spectroscopy. Warming of field-cooled and zero-field-cooled low-temperature saturation remanence displays magnetic phase transitions of titanium-rich titanohematite below 50 K and the Verwey transition of magnetite. A prominent irreversible decline characterizes zero-field cooling of room temperature saturation remanence. It typically sets out at ∼210 K and is most clearly developed in the lower part of the SMT zone, where low-temperature hysteresis measurements identified ∼210 K as the blocking temperature range of a titanohematite phase with a Curie temperature of around 240 K. The mechanism responsible for the marked loss of remanence is, therefore, sought in partial magnetic self-reversal by magnetostatic interaction of (titano-)magnetite and titanohematite. When titanohematite becomes ferrimagnetic upon cooling, its spontaneous magnetic moments order antiparallel to the (titano-)magnetite remanence causing an drastic initial decrease of global magnetization. The loss of remanence during subsequent further cooling appears to result from two combined effects (1) magnetic interaction between the two phases by which the (titano-)magnetite domain structure is substantially modified and (2) low-temperature demagnetization of (titano-)magnetite due to decreasing magnetocrystalline anisotropy. The depletion of titanomagnetite and superior preservation of titanohematite is characteristic for strongly reducing sedimentary environments. Typical residuals of magnetic mineral assemblages derived from basaltic volcanics will be intergrowths of titanohematite lamellae with titanomagnetite relics. Low-temperature remanence cycling is, therefore, proposed as a diagnostic method to magnetically characterize such alteration (palaeo-)environments. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscale magnetic material is the important topic in nanoscience and magnetism. Especially, gold nanoparticles chemisorbed by alkanethiols are one of the promising material for these purposes. However, magnetic interaction of magnetically active ligands grafted onto the surface of gold nanoparticles has not been investigated in detail. In order to elucidate the magnetic interaction in gold nanoparticles chemisorbed by alkanethiol systems, small slab gold cluster, such as Au10, and π-radical hybrid model systems were examined using the hybrid DFT method. [Copyright &y& Elsevier]

Abstract: The electronic structures of Ni2(dta)4I and Pt2(dta)2I complexes were examined by using UB3LYP calculations in terms of relation between magnetic interactions and structures of those complexes. The calculated effective exchange integrals (J ab) values by using experimental structures were −488 and −1274cm−1 for Ni2(dta)4I and Pt2(dta)4I complexes, respectively. Natural orbital (NO) analyses revealed the origin of the difference in their antiferromagnetic interactions. In order to explain a variety of structural phases in those complexes, such as averaged valence (AV), spin density wave (SDW), charge polarization (CP) and alternate charge polarization (ACP), potential and J ab surfaces were also investigated. The calculated potential surfaces explained experimental results that Ni2(dta)4I complex only took AVSDW phase, while Pt2(dta)4I complex underwent AVSDW, CP and ACP phases by temperature. [Copyright &y& Elsevier]

Abstract: A series of bis(4,4,4-trifluoro-1-R-1,3-butanedinato) Co(II) complexes with imino nitroxide radical(IM2py), [Co(Rtfc)2(IM2py)] (R=trifluoromethyl, phenyl, naphthyl, thienyl), was prepared and characterized by the X-ray analysis which demonstrated the stereospecific formation of the trans(CF3)-isomer with the trans disposition of the CF3 groups. The significant substituents effect on the UV–Vis spectra and magnetic properties were discussed in consideration of the inversion of the dπ(t2g) orbital levels leading to the orbital orthogonality or overlap with the SOMOπ∗ of IM2py in terms of the AOM parametrizations or spin-paring energy. [Copyright &y& Elsevier]

Abstract: We successfully synthesized and characterized two precursors for paramagnetic chelating ligands, N-p-anisyl-N-2-pyridylhydroxylamine and 2,6-bis(N-t-butylhydroxylamino)pyridine. The former can be regarded as a rare case since N,N-diarylhydroxylamines cannot be isolated in general because of facile autoxidation. The oxidation with silver(I) oxide gave radicals showing typical nitroxide ESR signals, but the resultant radicals were unstable under ambient conditions. Theoretical DFT calculation indicated that the bisnitroxide radical, pyridine-2,6-diyl bis(t-butyl nitroxide), had a triplet ground state. [Copyright &y& Elsevier]

Abstract: Oxidation of 9,9′(10H,10′H)-spirobiacridine with m-chloroperbenzoic acid gave a dinitroxide biradical derivative, SBDO, together with a monoradical, SBO. Their molecular and crystal structures were determined by X-ray crystallographic analysis. Magnetic measurements on a polycrystalline sample of SBDO revealed the presence of dominant antiferromagnetic interaction, which can be ascribed mainly to intermolecular interaction due to close contacts between two nitroxide groups. The intermolecular N–O distances were 3.176(2) and 3.184(2)Å. The diluted ESR experiments and the DFT calculation on a single molecule of SBDO indicated the ground triplet state. We also found that SBO worked as a versatile host for organic solvent molecules (CH2Cl2, CHCl3, CH3CN, ClC6H5, CH3OH, etc.). [Copyright &y& Elsevier]