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New metastable SmSi3−x (x=0–0.05) is obtained by high‐pressure high‐temperature synthesis (9.5 GPa, 870–1270 K). Powder diffraction data refinements reveal that the crystal structure of SmSi3 is isotypic to that of YbSi3 (space group I4/mmm, a=7.23634(5) Å, c=11.0854(1) Å). In the crystal structure, two types of Si2 dumbbells agglomerate into layers, which embed the samarium atoms. At ambient pressure, SmSi3 decomposes exothermally upon heating into Si and SmSi2−x. Single‐crystal structure refinements of a specimen SmSi3−x (x=0.05) reveal considerable electron density, which is not accounted for by the YbSi3‐type model. The additional maxima can be assigned to disorder which affects the samarium positions and induces silicon vacancies. Scanning transmission electron microscopy experiments evidence that the disorder can be attributed to extended defects. Magnetic measurements on SmSi3−x reveal van Vleck paramagnetic behavior and antiferromagnetic ordering at low temperatures. Computations within the local spin density approximation (LSDA and LSDA+U) on the crystal structure of SmSi3 reproduce the antiferromagnetic coupling as the favored long‐range order. Quantum chemical analysis of the chemical bonding in SmSi3 reveals two‐center two‐electron bonds within the Si2 dumbbells plus a total of a little less than four electrons in lone pairs at each silicon atom. [ABSTRACT FROM AUTHOR]

Soy protein is one kind of environment‐friendly nonbioactive plant protein with excellent properties. Paramagnetic γ‐Fe2O3 nanoparticles with a mean particle size of 7 nm are prepared by submerged circulative impinging stream reactor (SCISR). And a series of soy protein isolate (SPI)/Fe2O3 nanocomposites with excellent magnetic performance have been successfully prepared with glycerol as plasticizer and γ‐Fe2O3 as fillers. The results show that the strong hydrogen bonds are formed between polar amino acids of SPI and the fillers. The Fe2O3 nanoparticles exhibit homogeneous dispersion in the protein matrix. The resulting SPI/Fe2O3 nanocomposites exhibit good paramagnetism and good microwave absorbing properties at 2–18 GHz. In addition, the mechanical properties and thermal stability of soy protein materials are improved with the addition of Fe2O3 nanocomposites. The interactions between the fillers and matrix as well as between the fillers would influence the reinforcing effect of Fe2O3. These natural resources based on green functional materials would exhibit wide potential applications in electromagnetic interference shielding and packaging areas. [ABSTRACT FROM AUTHOR]

One ‐ dimensional (1D) transition metal oxide (TMO) nanostructures are actively pursued in spintronic devices owing to their nontrivial d electron magnetism and confined electron transport pathways. However, for TMOs, the realization of 1D structures with long ‐ range magnetic order to achieve a sensitive magnetoelectric response near room temperature has been a longstanding challenge. Herein, we exploit a chemical hydric effect to regulate the spin structure of 1D V – V atomic chains in monoclinic VO2 nanowires. Hydrogen treatment introduced V3+ (3d2) ions into the 1D zigzag V – V chains, triggering the formation of ferromagnetically coupled V3+ – V4+ dimers to produce 1D superparamagnetic chains and achieve large room ‐ temperature negative magnetoresistance (−23.9 %, 300 K, 0.5 T). This approach offers new opportunities to regulate the spin structure of 1D nanostructures to control the intrinsic magnetoelectric properties of spintronic materials. Die Spinstruktur der eindimensionalen V ‐ V ‐ Ketten in monoklinen VO2 ‐ Nanodrähten wurde durch Wasserstoffbehandlung modifiziert, wodurch V3+ ‐ Ionen und ferromagnetisch gekoppelte V3+ ‐ V4+ ‐ Dimere in den Ketten erzeugt wurden. Die neue Struktur besteht aus superparamagnetischen Ketten und zeichnet sich durch einen großen negativen Magnetwiderstand bei Raumtemperatur aus. [ABSTRACT FROM AUTHOR]

The graphene system is actively pursued in spintronics for its nontrivial sp electron magnetism and its potential for the flexible surface chemical tuning of magnetoelectronic functionality. The magnetoresistance (MR) of graphene can be effectively tuned under high magnetic fields at cryogenic temperatures, but it remains a challenge to achieve sensitive magnetoelectric response under ambient conditions. We report the use of surface modulation to realize superparamagnetism in reduced graphene oxide (rGO) with sensitive magnetic field response. The superparamagnetic rGO was obtained by a mild oxidation process to partially remove the thiol groups covalently bound to the carbon framework, which brings about large low-field negative MR at room temperature (−8.6 %, 500 Oe, 300 K). This strategy provides a new approach for optimizing the intrinsic magnetoelectric properties of two-dimensional materials. [ABSTRACT FROM AUTHOR]

Compounds [Fe3Ln(tea)2(dpm)6] ( Fe3Ln; Ln= Tb-Yb, H3tea=triethanolamine, Hdpm=dipivaloylmethane) were synthesized as lanthanide(III)-centered variants of tetrairon(III) single-molecule magnets (Fe4) and isolated in crystalline form. Compounds with Ln=Tb-Tm are isomorphous and show crystallographic threefold symmetry. The coordination environment of the rare earth, given by two tea3− ligands, can be described as a bicapped distorted trigonal prism with D3 symmetry. Magnetic measurements showed the presence of weak ferromagnetic Fe ⋅⋅⋅Ln interactions for derivatives with Tb, Dy, Ho, and Er, and of weak antiferromagnetic or negligible coupling in complexes with Tm and Yb. Alternating current susceptibility measurements showed simple paramagnetic behavior down to 1.8 K and for frequencies reaching 10000 Hz, despite the easy-axis magnetic anisotropy found in Fe3Dy, Fe3Er, and Fe3Tm by single-crystal angle-resolved magnetometry. Relativistic quantum chemistry calculations were performed on Fe3Ln (Ln=Tb-Tm): the ground J multiplet of Ln3+ ion is split by the crystal field to give a ground singlet state for Tb and Tm, and a doublet for Dy, Ho, and Er with a large admixture of mJ states. Gyromagnetic factors result in no predominance of gz component along the threefold axis, with comparable gx and gy values in all compounds. It follows that the environment provided by the tea3− ligands, though uniaxial, is unsuitable to promote slow magnetic relaxation in Fe3Ln species. [ABSTRACT FROM AUTHOR]

Palaeomagnetism of 273 specimens from 24 sites isolated a well-defined characteristic remanent magnetization (ChRM) direction on AF and thermal demagnetization in seven host carbonate and 14 ore mineralization sites from the Galmoy Zn–Pb deposit. Thermal decay and saturation remanence data show that the ChRM is carried dominantly by single domain magnetite. Palaeomagnetic field stability tests indicate a post-brecciation and post-folding ChRM. The ChRM directions from the host rock and mineralized sites are indistinguishable at 95% confidence and give a palaeopole at 41.5°S, 8.4°W (dp = 1.5°, dm = 3.0°) with an age of 290 ± 9 Ma on the Laurentian apparent polar wander path. This Early Permian age at Galmoy records Variscan orogenesis and suggests an epigenetic model in which mineralization occurred during cooling from the regional Variscan thermal episode. [ABSTRACT FROM AUTHOR]

A previous self-consistent field molecular orbital method, able to describe systems having a large number of unpaired electrons, n, is reviewed and improved. This method is applied to the study of paramagnetism in large (1,000–16,000 atoms) zigzag carbon nanotubes, represented by their n values. The computational scheme is based on the Hückel neglect differential overlap approach. It is shown that dependence of n on the semiempirical parameters is very small, and so they can be removed from the calculation. Enhancement of the paramagnetism (increase of n), by use of a strong external magnetic field, is also studied. Finally, the dependence of the Fermi one-electron potential energies and the spin atomic densities on both the parameters and the shape of the nanotubes is analyzed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SRM) have a simpler and more rugged construction than conventional ac motors, and hence are suitable for low-cost variable-speed drives in many industrial applications. However, the need to use a traditional position sensor for their control is one of the disadvantages of SRM from the standpoints of cost, size, and reliability. For practical use, there is a need for sensorless drive of SRM. This paper describes position-sensorless control of SRM based on a simple expression of their nonlinear magnetization characteristics. Successful experiments using a 1.5-kW, 5400-rpm SRM with a 6/4 pole configuration have verified the practicability of the proposed sensorless control scheme. © 2001 Scripta Technica, Electr Eng Jpn, 137(2): 52–60, 2001 [ABSTRACT FROM AUTHOR]

The direction of the toroidal magnetic field near the edge of the plasma in RIP is reversed compared to that at the center. During quasi-steady-state or steady-state operations, the toroidal magnetic field on the wall its is supported by the external current stressing through the toroidal coil CT or the shell that covers the plasma, while the nonreversed toroidal field in the central region is maintained automatically by the "dynamo effect." Plasmas possess paramagnetism, a current at the plasma center flowing parallel to the magnetic field, intensifies the original magnetic field in the axial direction.

The synthesis, electrical resistivity ρ(T), and magnetic susceptibility χ(T) of single‐crystalline NiTe and NiTe2 are reported. The two compounds display good metallic behavior with χ(300 K) ≈3.6 μΩ cm, and ρ(T) at low temperature can be well described by Fermi‐liquid theory. χ(T) measurements suggest that both samples exhibit Pauli‐like paramagnetism. The Pauli magnetic susceptibility of NiTe is strongly enhanced, implying it is in proximity to magnetic instability. [ABSTRACT FROM AUTHOR]