Materials Literature
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It is reported that Nd-Fe-B magnetic powders prepared by utilizing the HDDR (hydrogenation, disproportionation, desorption, and recombination) phenomena exhibit high coercivity, and the addition of Co, Ga, and Zr induces magnetic anisotropy in these powders. HDDR phenomena are caused by the heat treatment in hydrogen…
We report on the magnetic properties of the Cr-based diluted magnetic semiconductors ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$Se and ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$S (x0.01). The specific heat was measured in the temperature range…
The plane-wave pseudopotential (PWPP) method is used to perform density-functional-theory (DFT) calculations for two grain boundaries in aluminum studied previously using the embedded-atom method (EAM) and high-resolution transmission electron microscopy: (1) a \ensuremath{\Sigma}=11 (11\ifmmode\bar\else\textasciimacr…
The formation of polarons and bipolarons in conjugated polymers with nondegenerate ground states is studied theoretically. We use the Pariser-Parr-Pople model combined with the Su-Schrieffer-Heeger model of electron-lattice coupling and a Brazovskii-Kirova-type symmetry-breaking interaction. The relative stability of…
We report the formation of several members of the recently discovered class of R3(Fe,T)29 compounds and some of their intrinsic properties. Focusing on materials with T=Ti and Cr, we have prepared R3(Fe,Ti)29 (R=Ce, Pr, Nd, Sm) and R3(Fe,Cr)29 (R=Ce, Nd, Sm) compounds which all feature the novel monoclinic crystal str…
Extremely well resolved Si 2p core-level spectra from the clean Si(111)7\ifmmode\times\else\texttimes\fi{}7 surface have been obtained at \ensuremath{\sim}100 K. Surface-shifted components become visible to the naked eye. Contributions from the constitutive entities of the complex 7\ifmmode\times\else\texttimes\fi{}7…
A large intrinsic magnetoresistance has been found near the ferromagnetic transition of metallic manganese oxides with perovskite-type crystal structure. The magnetic and transport properties were measured on bulk and thin-film La1−xAxMnO3+δ with A=Ca,Sr,Ba. Assuming the double-exchange model proposed by Zener [Phys.…
Upon irradiating poly(p-phenylene vinylene) thin films with white light in air (total exposure \ensuremath{\sim}5 J/${\mathrm{cm}}^{2}$), an enhancement of about forty times in photocarrier generation and a similar reduction in the photoluminescence intensity are observed. The wavelength and electric-field dependence…
New rare-earth (R), iron-rich ternary intermetallic compounds of the form R3(Fe,M)29 with the monoclinic Nd3(Fe,Ti)29 structure (space group P21/c, ♯14, Z=2) have recently been shown to form with R=Ce, Nd, Pr, Sm, and Gd, and M=Ti, V, Cr, and Mn. This novel structure is derived from the alternate stacking of Th2Zn17 a…
There exists a duality in the structure between a non-Bravais-type quasilattice and its Fourier transform. The diffraction pattern of a quasicrystal modelled by the quasi-lattice is dominated by this structure of the Fourier transform and its reflections are classified into main reflections and several groups of satel…
In the series of ordered DO3 solid solutions Fe3−xMnxSi, field-induced transitions have previously been found to occur for antiferromagnetic alloys with values of x near 1.70. The present work has determined a region of composition in which antiferromagnetism is the low-field, low-temperature state and gives the varia…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared Studies of the Microdomains and Mesomorphic Properties of 4'-Cyano-4-biphenyl [4-(4-pentenyloxy)]benzoate Coated on SilicaY. W. Zhou, M. Jaroniec, and R. K. GilpinCite this: Anal. Chem. 1994, 66, 22, 4100–4104Publication Date (Print):November 15, 1994Publication His…
The gypsum-type structure of the title compound, weinschenkite [churchite(Y)], is confirmed. The H-atom positions could not be located. The structures of gypsum [Cole & Lancucki (1974). Acta Cryst. B30, 921929], CaSeO 4 . 2H 2 O [Kruger & Abriel (1991). Acta Cryst. C47, 1958-1959] and weinschenkite are isotypic. Howev…
The potassium salt containing the [H 4 β-PtMo 6 O 24 ] 4− polyanion, which has approximate 2mm symmetry (bent structure), has been isolated and its structure determined by single-crystal X-ray diffraction. This polyanion is an isomeric form of the 3m (flat-structure) species
Electronic energy bands of metallic ${\mathrm{TiTe}}_{2}$ are calculated, and the transport masses (n/m${)}_{\mathrm{\ensuremath{\alpha}}\mathrm{\ensuremath{\beta}}}$ are evaluated. Comparison with the measured resistivity shows that this is an ordinary metal with a moderate electron-phonon interaction in the usual qu…
We have fabricated Ni filaments by nickel precipitation into a porous silicon matrix, making Ni filaments of about 200 Å in diameter and 30 μm in length separated by ∼500 Å silicon walls. This composite material demonstrates strong magnetic anisotropy perpendicular to the surface due to shape anisotropy of the Ni fila…
We have developed a novel Lagrangian–Eulerian numerical scheme to model the dynamics of dense hard-disk suspensions with many-body hydrodynamic interactions in an incompressible Newtonian solvent. A simple derivation of analytical solution of lubrication force between disks is given. Reasonable agreement of viscosity…
We report a systematic analysis of the crystal-field spectra of four fluoride compounds containing tetravalent actinide ions. The first part of this work [J. Chem. Phys. 95, 7194 (1991)] provided interpretation of the absorption spectra of UF4, NpF4, and PuF4. To extend our analysis to heavier elements of the series,…
Electron microscopy and initial magnetization studies at elevated temperatures were performed on two die-upset rare-earth magnets with bulk compositions Nd13.75Fe80.25B6 and Pr13.75Fe80.25B6. In both compositions the intergranular phase is amorphous and occurs primarily on those surfaces parallel to the tetragonal 2-1…
The effect of changing stress on the magnetization of ferromagnetic materials leads to behavior in which the magnetization may increase, or decrease, when exposed to the same stress under the same external conditions. A simple empirical law seems to govern the behavior when the magnetization begins from a major hyster…