Materials Literature
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Nb-doped SrTiO3 (STO) thin films (Nb, 0<x<100 mol%) with a-axis orientation have been prepared on nondoped STO (100) and LaAlO3 (100) single crystals using a pulsed laser deposition technique. Solid-solution films are formed between STO and SrNbO3 without any impurity phases. Electrical conductivities of…
Micromagnetic calculations using a finite element technique rigorously describe the magnetic properties of novel, isotropic rare-earth-based composite magnets. Numerical results obtained for a composite material of Nd2Fe14B, SmCo5 or Sm2(Fe0.8Co0.2)17N2.8 and α-Fe particles show that remanence, coercivity, and coerciv…
A colossal magnetoresistance effect with more than a thousandfold change in resistivity (ΔR/RH=127 000% at 77 K, H=6 T) has been obtained in epitaxially grown La-Ca-Mn-O thin films. The effect is negative and isotropic with respect to the field orientations. The magnetoresistance is strongly temperature dependent, and…
Landau quantization of the \ensuremath{\pi} energy bands of a carbon nanotube is calculated within the tight-binding approximation. The energy bands do not show explicit Landau levels, but they do have energy dispersion for all values of magnetic field. The energy bandwidth shows oscillations with a period that is sca…
The 1.681-eV luminescence center characteristically observed in chemical-vapor-deposited diamond films is studied in a homoepitaxially grown diamond film. Homoepitaxial growth relaxes the strain typical for films grown on heterosubstrates with lattice mismatch, thus reducing dramatically the optical linewidths down to…
Though the anomalous antiferromagnetism of zinc ferrite was a subject of intensive studies in the past, the unusually high magnetization of coprecipitated zinc ferrite at low temperatures has drawn renewed interest among researchers. The local structures of zinc ferrites around Fe and Zn atoms are measured using exten…
An extension of the hysteresis model has been developed that takes into account the effects on the hysteresis curves of eddy currents in electrically conducting media. In the derivation presented it is assumed that the frequency of the applied field is low enough (or the thickness of the material medium small enough)…
Giant magnetotransport phenomena including the field-induced nonmetal-metal transition have been found in single crystals of La 1- x Sr x MnO 3 near the critical composition ( x ≈0.17) for the nonmetal-metal transition and in the temperature region around the magnetic phase transition. Change of the resistivity shows…
The planarity of the aromatic stage of two-dimensional Si and Ge layers are theoretically investigated by first-principles total-energy calculations. While a C atom prefers to form the flat aromatic stage, i.e., graphite, Si and Ge prefer to form the corrugated aromatic stage. Si can be said to be the critical element…
The Li diffusion in Li2S at high temperatures was investigated by quasielastic neutron scattering techniques on a single crystal of 7Li2S. It is shown by using polarized neutrons that the scattering is almost purely incoherent. The data were analysed in terms of an extended Chudley-Elliott jump diffusion model. The Li…
Powder neutron diffraction measurements were made on CuCl and CuBr solid ion conductors over large ranges of temperature in the cubic gamma phase (sphalerite structure). Anharmonic data treatment based on the Gram-Charlier expansion showed significant contributions up to fourth order for the thermal parameters of Cu.…
The nature of the holmium order in the reentrant superconductor (${T}_{c}=7.5 \mathrm{K}$) Ho${\mathrm{Ni}}_{2}$${\mathrm{B}}_{2}$C is revealed by neutron scattering. Upon cooling a transversely polarized oscillatory magnetic state is formed (${T}_{M}\ensuremath{\approx}8 \mathrm{K}$), characterized by a wave vector (…
We report on a scanning tunneling microscopy study demonstrating silicon mass transport and the resulting roughening of the surface during Sb deposition on Si(111). It is found that small amounts of Sb, which cause the Sb-induced d-(7×7) reconstruction, lead to Si island formation due to the replacement of Si atoms by…
Abstract The morphological changes induced to segmented polyurethane elastomers by varying the NCO/OH ratio during the second step of polymerization, while keeping constant the total hard‐segment content (∼ 30%), were studied by means of fourier transform infared spectroscopy (FTIR), differential scanning calorimetry…
Debye-H\"uckel theory for spheres of diameter $a$ with charges $^{\ifmmode\pm\else\textpm\fi{}}q$ is extended to general dimension $d$. Explicit results include Bjerrum association of +/- ions and the dipole-ionic solvation energy. For all $d>2$ a critical point terminates conducting-liquid-conducting-vapor coexist…
Ge-nanocrystal-embedded SiO2 glasses were prepared by a sol-gel process. The glasses synthesized through hydrolysis of Si(OC2H5)4 and GeCl4 were heated in the presence of hydrogen at 400–700 °C, in which Ge4+ ions were reduced to precipitate nanosized Ge crystals. Glasses doped with Ge nanocrystals of diameter of ∼5 n…
Abstract Small‐angle x‐ray scatting (SAXES) and transmission electron microscopy (TEM) have been applied to study polymer morphologies of CO 2 ,‐blown rigid polyurethane foam samples of varying isocyanate index. The results are consistent with an irregular (meso) phase segregated structure with phase boundaries showin…
We report lattice and electronical properties of BaTiO3:La powders and ceramics with 0<xLa<20 at.%. Dielectric measurements and x-ray scattering evidence a continuous decrease of the ferroelectric transition temperature when the La content is increased. For xLa=20 at.%, no dielectric maximum is found for temperatures…
Optically controlled planar orientation of liquid crystal molecules with polarized light is used to make phase gratings in liquid crystal media. The electro-optical properties of liquid crystal linear and chirped gratings are discussed.
We report on detailed neutron diffraction studies of both pinned and moving magnetic flux line lattices in $2H\ensuremath{-}\mathrm{Nb}{\mathrm{Se}}_{2}$. For field-cooled, pinned lattices, we are able to make a detailed quantitative comparison with the theory of Larkin and Ovchinnikov and find excellent agreement. In…