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The effects of the coating surface orientation of the α-Fe soft magnetic layer on the Sm(Fe0.8Co0.2)12 hard magnetic phase and the volume fraction of α-Fe, VFe, on the maximum energy product, (BH)max of exchange-coupled Sm(Fe0.8Co0.2)12/α-Fe nanocomposite magnet particles were micromagnetics OOMMF package was systematically investigated. The (BH)max of the reference model, Sm(Fe0.8Co0.2)12 particles without Fe layer, was 630 kJ/m3. In contrast, in the nanocomposite magnet particle model with soft magnetic layers on both sides of the hard magnetic phase, (BH)max reached a maximum value of 657 kJ/m3 at VFe = 12% (Fe layer thickness, tFe = 2 nm). In the model with α-Fe coating on the top and bottom surfaces of the hard magnetic phase, (BH)max = 636 kJ/m3 at VFe = 4% (tFe = 2 nm). Furthermore, the coating of the soft magnetic phase on both sides of the hard phase particles reduces the magnitude of the demagnetizing field, Hd of the nanocomposite magnet particles, indicating that the side coating of the soft magnetic phase is effective in increasing (BH)max. These findings allow for a greater degree of freedom in the design of nanocomposite magnets by adjusting not only the VFe volume fraction of the hard/soft phases but also their arrangement.

In real materials, a spin quantum number assumes a fixed value, which makes it challenging to realize a crossover between quantum and classical spin regimes. Here the authors demonstrate such a crossover in a weakly coupled chain compound by controlling the amount of quantum correlations, in the form of the inverse spin quantum number, with external pressure.

The formation of nanocomposite Nd-Fe-B/Mo/FeCo multilayered magnet films using the infrared laser annealing technique. The perpendicular magnetic anisotropy of the film with Mo interlayer was larger than that of the film without Mo interlayer before annealing. Magnetic properties of both films were drasticly changed from soft magnetism to hard magnetism with in-plane magnetic anisotropy after the infrared laser annealing process at 760°C. Coercivity of in-plane annealed film with Mo interlayer was about 10 kOe which was double that of the film without Mo interlayer. In second quadrant, squareness of demagnetization curve of infrared laser annealing processed film with Mo interlayer was better than that of film without Mo interlayer. The infrared laser annealing process crystallizes the amorphous phase of the Nd-Fe-B layer as well as the multi-step annealing, even though the infrared laser annealing process time is only 1/100 of the process time of the multi-step annealing using halogen lamps reported previously.

The Nd-Fe-B/Mo/Fe-Co multilayered films on MgO(001) were fabricated by UHV sputtering method. The as-deposited films showed soft magnetic properties with weak perpendicular magnetic anisotropy, and after annealing above 650°C, these films showed in-plane magnetic anisotropy, good squareness, and hard magnetic properties with high coercivity of about 8 kOe. The (220) peak of Nd2Fe14B was identified in the XRD pattern after annealing of the film, which means that the c-axis, which is the easy axis of magnetization, points in the plane of the film, consistent with the measurement of the magnetization curve. The positive peak of ΔM plot of in-plane direction of the film annealed at 800°C was shown. This result suggests existence of exchange coupling between the Nd-Fe-B and Fe-Co layers in the in-plane anisotropic multilayered film with monoatomic Mo interlayer.

To develop a new spin-crossover functional material, a magnetic hybrid compound [Fe(qsal)2][Ni(mnt)2] was designed and synthesized (Hqsal = N-(8-quinolyl)salicylaldimine, mnt = maleonitriledithiolate). The temperature dependence of magnetic susceptibility suggested the coexistence of the high-spin (HS) Fe(III) cation and π-radical anion at room temperature and a magnetic transition below 100 K. The thermal variation of crystal structures revealed that strong π-stacking interaction between the π-ligand in the [Fe(qsal)2] cation and [Ni(mnt)2] anion induced the distortion of an Fe(III) coordination structure and the suppression of a dimerization of the [Ni(mnt)2] anion. Transfer integral calculations indicated that the magnetic transition below 100 K originated from a spin-singlet formation transformation in the [Ni(mnt)2] dimer. The magnetic relaxation of Mössbauer spectra and large thermal variation of a g-value in electron paramagnetic resonance spectra below the magnetic transition temperature implied the existence of a magnetic correlation between d-spin and π-spin.

Diatomaceous deposits are mixtures of diatom tests (biogenic silica)and argillaceous materials. Biogenic silica migrates in the deposits as its mineral phase transforms during burial diagenesis, concentrating and diluting organic matter and argillaceous materials, and changing pore properties. The migration is considered through a simple burial diagenesis model. As a result, analytical data related to various properties including the properties of source and reservoir rocks of the Onnagawa Formation, are explained.The migration of biogenic silica during opal-A / CT transformation emphasizes a slight compositional difference in diatomaceous deposits and forms hard (opal-CT porcelanite)-soft (opal-CT siliceous mudstone) alternating beds. The silica flows from the proto-siliceous mudstone into the proto-porcelanite, which concentrates the argillaceous materials and organic matter in the siliceous mudstone, improving its source rock potential. In addition, due to the migration, the compositional difference is emphasized even in proto-porcelanite (hard), and light-dark colored porcelanite alternating beds are formed and become distinct. Conversely, during the opal-CT / Quartz transformation, the silica flows from the light-colored porcelanite into the dark-colored porcelanite, and the porosity of light-colored porcelanite is increased, and that of dark-colored porcelanite is decreased and chertified. Since compaction during opal-CT / Quartz transformation is more advanced than during opal-A / CT transformation, the increased porosity tends to be maintained. This phenomenon forms a double porosity reservoir in which light-colored porcelanite with high porosity and dark-colored porcelanite with dense fractures, alternate with each other.The improvement of source and reservoir rock properties is promoted as biogenic silica migration increases. Therefore, better source and reservoir rocks are formed adjacent to each other by the diagenesis of diatomaceous deposits with more primary diatom test contents. The primary diatom test contents are estimated from the Al2O3/TiO2 when chemical compositions of diatom tests and argillaceous materials are properly estimated. [ABSTRACT FROM AUTHOR]

In solid materials, the parameters relevant to quantum effects, such as the spin quantum number, are basically determined and fixed at the chemical synthesis, which makes it challenging to control the amount of quantum correlations. We propose and demonstrate a method for active control of the classical-quantum crossover in magnetic insulators by applying external pressure. As a concrete example, we perform high-field, high-pressure measurements on CsCuCl3, which has the structure of weakly-coupled spin chains. The magnetization process experiences a continuous evolution from the semi-classical realm to the highly-quantum regime with increasing pressure. Based on the idea of "squashing” the spin chains onto a plane, we characterize the change in the quantum correlations by the change in the value of the local spin quantum number of an effective two-dimensional model. This opens a way to access the tunable classical-quantum crossover of two-dimensional spin systems by using alternative systems of coupled-chain compounds. [ABSTRACT FROM AUTHOR]

The microscopic magnetic properties of high-quality GdN thin films have been investigated by electron spin resonance (ESR) and ferromagnetic resonance (FMR) measurements. Detailed temperature dependence ESR measurements have shown the existence of two ferromagnetic components at lower temperatures, which was not clear from the previous magnetization measurements. The temperature, where the resonance shift occurs for the major ferromagnetic component, seems to be consistent with the Curie temperature obtained from the previous magnetization measurement. On the other hand, the divergence of line width is observed around 57K for the minor ferromagnetic component. The magnetic anisotropies of GdN thin films have been obtained by the analysis of FMR angular dependence observed at 4.2K. Combining the X-ray diffraction results, the correlation between the magnetic anisotropies and the lattice constants is discussed. [ABSTRACT FROM AUTHOR]

Chemical compositions of rock-forming minerals in the pelitic rock, the siliceous rock, the felsic tuff, and the dolerite intrusions from the Onnagawa Formation in Ayukawa oil and gas field were compiled, based on their SEM-EDS analysis as basic data. They have been used for geochemical simulations to evaluate the precipitation and the dissolution of mineral in the water-rock interaction systems. The analyzed mineral groups were feldspar, zeolite, carbonate mineral and clay mineral. They seem to have relatively wide variation of their chemistry or to be important minerals in the simulation. This examination also revealed that the mineral described as talc in the former article (Okubo, et al.,1996) is pyrophyllite. Therefore its occurrence and chemical composition is also reported. [ABSTRACT FROM AUTHOR]

In this paper we discuss (ε, δ)-Freudenthal Kantor triple systems with certain structure on the subspace L_2 of the corresponding standard embedding five graded Lie (super)algebra L(ε, δ) := L-2 Φ L-1 Φ L0 φ L1 φ L2, [Li, Lj] Ç Li+j. We recall Lie and Jordan structures associated with (ε, δ)-Freudenthal Kantor triple systems ([26], [27]) and the give results for unitary and pseudo-unitary (ε, δ)-Freudenthal Kantor triple systems. Further, we give the notion of Aδ-structurable algebras and connect them to (--1, δ)-Freudenthal Kantor triple systems and the corresponding Lie (super) algebra construction. [ABSTRACT FROM AUTHOR]

In this paper, we define the concept of a triality group and consider the group associated with algebras. In particular, we study a characterization of this group for symmetric composition algebras and other nonassociative algebras. [ABSTRACT FROM AUTHOR]

A single-crystal S = 3/2 perfect kagome lattice antiferromagnet, KCr3(OH)6(SO4)2 (Cr-jarosite), has been studied by X-band and high-frequency electron spin resonance (ESR). The g-values perpendicular to the kagome plane (c-axis) and in the plane were determined to be gc = 1.9704 ± 0.0002 and gξ = 1.9720 ± 0.0003, respectively, by high-frequency ESR observed at 265 K. Antiferromagnetic resonances (AFMRs) with an antiferromagnetic gap of 120 GHz were observed at 1.9 K, which is below TN = 4.5 K. The analysis of AFMR modes using the conventional molecular field theory gave dp = 0.27 K and dz = 0.07 K, where dp and dz are in-plane and out-of-plane components of d vector of the Dzyaloshinsky–Moriya (DM) interaction, respectively. On the basis of these results and the exchange interaction of J = 6.15 K estimated by Okuta et al., the ground state of Cr-jarosite was discussed in connection with the Monte Carlo simulation results with classical Heisenberg spins on the kagome lattice by Elhajal et al. Finally, the angular dependence of the linewidth and lineshape observed at 296 K by X-band ESR showed the typical behavior of a two-dimensional Heisenberg antiferromagnet, suggesting the good two-dimensionality of Cr-jarosite. [ABSTRACT FROM AUTHOR]

We introduce a notion of pre-structurable algebras based on the structurable algebra of Allison, as well as Lie algebras that satisfy triality. [ABSTRACT FROM AUTHOR]

In a frustrated J1-J2 chain with the nearest-neighbor ferromagnetic interaction J1 and the next-nearest-neighbor antiferromagnetic interaction J2, novel magnetic states such as a spin-nematic state are theoretically expected. However, they have been rarely examined in experiments because of the difficulty in obtaining suitable model compounds. We show here that the quasi-one-dimensional antiferromagnet NaCuMoO4(OH), which comprises edge-sharing CuO2 chains, is a good candidate J1-J2 chain antiferromagnet. The exchange interactions are estimated as J1 = -51K and J2 = 36K by comparing the magnetic susceptibility, heat capacity, and magnetization data with the data obtained using calculations by the exact diagonalization method. High-field magnetization measurements at 1.3K show a saturation above 26 T with little evidence of a spin nematic state expected just below the saturation field, which is probably due to smearing effects caused by thermal fluctuations and the polycrystalline nature of the sample. [ABSTRACT FROM AUTHOR]

We give a definition of new triple systems and study the correspondence between triple and bilinear products for many triple systems. [ABSTRACT FROM AUTHOR]

Some symmetries of time-dependent Schrödinger equations for inverse quadratic, linear, and quadratic potentials have been systematically examined by using a method suitable to the problem. Especially, the symmetry group for the case of the linear potential turns out to be a semidirect product SL(2,R) ⓈT[sub 2](R) of the SL(2,R) with a two-dimensional real translation group T[sub 2](R). Here, the time variable t transforms as t→t[sup ′]=(ct+d)/(at+b) for real constants a, b, c, and d satisfying bc-ad=1 with an accompanying transformation for the space coordinate x. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Various light sources for plant production have been developed to establish a completely controlled factory. We propose a pulse light source using Xe discharge. For the rapid growth of the plant, an intense light covering the absorption spectral region of chlorophyll is demanded, and periodic irradiation is also required because the photosynthetic reaction has a certain period. In this study, Sr3MgSi2O8:Eu,Mn phosphor powders with various Eu and Mn content, which show two emission peaks in the absorption region of photosynthetic pigment and phytochrome, were synthesized, and were analyzed using X-ray diffraction, photoluminescence and electron spin resonance spectroscopy. It was found that the exchange-coupled Mn-Mn and Eu-Mn pairs lead the rapid decay of Mn emission and efficient energy transfer from Eu and Mn ions, respectively. A plasma tube array panel using the phosphor was also fabricated and the similar emission spectrum of Sr3MgSi2O8:Eu,Mn is obtained under vacuum-UV excitation in comparison to the UV excitation. [ABSTRACT FROM AUTHOR]