Materials Literature
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The high-frequency permittivity of composites consisting of a lattice of ferromagnetic wires is investigated. Experimental results using free space or coaxial line microwave measurements are reported. It is shown that the dielectric response is strongly dependent on the magnetic properties of the wires. Negative real…
We present an analysis of the distribution of end groups within a urea-functionalized poly(propyleneamine) dendrimer of the fourth generation by small-angle neutron scattering (SANS). The phenyl end groups have been deuterated to enhance their contrast. The SANS experiments are performed using solution of the labeled…
Three octahedral complexes containing a (cis-cyclam)iron(III) moiety and an O,N-coordinated o-iminobenzosemiquinonate pi radical anion have been synthesized and characterized by X-ray crystallography at 100 K: [Fe(cis-cyclam)(L(1-3)(ISQ))](PF(6))(2) (1-3), where (L(1-3)(ISQ)) represents the monoanionic pi radicals der…
A study of the crystallographic and magnetic structure of the double perovskites Sr 2 MnMoO 6 , Sr 2 MnWO 6 and Ca 2 MnWO 6 has been carried out on polycrystalline samples using neutron powder diffraction (NPD) data. A room temperature analysis of high-resolution NPD patterns has shown that these compounds crystallize…
A technique (laser deposition of Zn/W multilayers) for producing stable nanocrystalline (nc) Zn films free of undesirable imperfections down to a grain size of d=6 nm is presented. These films exhibited grain size softening (inverse Hall–Petch effect) for d⩽11 nm, providing support that this can be a real phenomenon i…
Monte Carlo simulations using a three-dimensional lattice model studied the Ruderman–Kittel–Kasuya–Yosida (RKKY) indirect exchange interaction of doped magnetic Co ions in ZnO films. The results of the calculations show that the RKKY interaction in Co-doped ZnO is long ranged and its magnitude is proportional to R−1 (…
The small-amplitude radial oscillations of a gas microbubble encapsulated by a viscoelastic solid shell and surrounded by a slightly compressible viscoelastic liquid are studied theoretically. The Kelvin–Voigt and 4-constant Oldroyd models are used to describe the viscoelastic properties of the shell and liquid, respe…
The dielectric behaviour of Ba(Ti 1−y Ce y )O 3 solid solutions ( y = 0–0.3) has been studied. A small amount of Ce doping ( y = 0.02) has weak influence on the dielectric behaviour of Ba(Ti 1−y Ce y )O 3 . With increasing Ce concentration, three phase transitions of pure BaTiO 3 are pinched into one rounded dielectri…
The synthesis and photochemistry of a new photolabile protecting group for carboxylic acids based on 8-bromo-7-hydroxyquinoline (BHQ) is described. BHQ possesses a greater single photon quantum efficiency than 4,5-dimethoxy-4-nitrobenzyl ester (DMNB) and 6-bromo-7-hydroxycoumarin-4-ylmethyl (Bhc), and it has sufficien…
We investigated carbon nanotube growth by means of methane chemical vapor deposition on ultrafine silicon patterns prepared by synchrotron-radiation lithography. Grown nanotubes formed suspended bridges between pillars when pillar spacing was comparable to pillar height. Network-like interconnections were obtained on…
Thin films of Nd3+-substituted bismuth titanate, (Bi4.00−y,Ndy)Ti3.00O12 (BNT), Nd3+/V5+-cosubstituted bismuth titanate, (Bi4.00−y,Ndy)(Ti3.00−xVx)O12 (BNTV), and La3+-substituted bismuth titanate, (Bi3.25,La0.75)Ti3.00O12 (BLT) were fabricated on the (111)Pt/Ti/SiO2/(100)Si substrates by a chemical solution depositio…
Centimeter long single-walled carbon nanotube strands synthesized using chemical vapor deposition method were characterized using microscopy, micro-Raman spectroscopy, and small-angle X-ray diffraction techniques. The strands are large collections of well-aligned nanotube bundles, which consist of well-arranged single…
Large yield of β-Ga2O3 nanorods with metal Ga tip were efficiently synthesized. They were deposited on surface of amorphous C fibers by decomposition of Ga2O vapor at around 1000 °C, where Ga2O vapor was produced at 1360 °C by a reaction between pure Ga2O3 and active carbon powders. The nanorods had diameters ranging…
A simultaneous analysis of high-resolution directional Compton profiles and two-dimensional angular correlation of positron annihilation experimental data has been performed by studying both a directional anisotropy of measured spectra and reconstructed densities. The results were compared with theoretical fully-relat…
We show for the intermediate valence compound YbAl$_{3}$ that the high field (40 $\lesssim B \lesssim$ 60T) effective masses measured by the de Haas-van Alphen experiment for field along the $<111>$ direction are smaller by approximately a factor of two than the low field masses. The field $B^{*} \sim$ 40T for this re…
For 40 million years, diatoms have dominated the reverse weathering of silica on Earth. These photosynthetic protists take up dissolved silicic acid from the water and precipitate opaline silica to form their cell wall. We show that the biosilica of diatoms is an effective pH buffer, enabling the enzymatic conversion…
The results of the X-ray, microscopic, magnetic, and dielectric measurements performed for PFN single crystals and ceramic samples are presented. The influence of the technological conditions on selected physical properties of the materials examined is shown.
Ultrananocrystalline diamond (UNCD) thin films consist of 2–5 nm grains of pure sp3-bonded carbon and ∼0.5-nm-wide grain boundaries with a disordered mixture of sp2- and sp3-bonded carbon. UNCD exhibits many interesting materials properties that are a direct consequence of its nanoscale morphology. In this work, we re…
Individual paramagnetic defect centers in diamond nanocrystals have been investigated by low-temperature high-resolution optical spectroscopy. Narrow fluorescence excitation spectral lines have been found, indicating transitions between individual spin sublevels. Spectral diffusion is explained by cross relaxation amo…
Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of high-quality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single cry…