Materials Literature
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We report on the structural, dielectric, and optical properties of barium strontium titanate–magnesium oxide composite (BST-MgO) thick films fabricated by the electrophoretic deposition technique. The structure and morphology of the films were analyzed by x-ray diffraction and scanning electron microscopy, respectivel…
Abstract The influence of the concentration of paraffin wax on the penetration rate, P , and the average diffusion coefficient, D , of kerosene in an SBR–NR composite and also on the coefficient of viscosity were investigated. All decreased with the addition of wax. Also, the effect of the concentration of paraffin wa…
Abstract Toluene diisocyanate reacts with poly(propylene glycol) during the synthesis of some urethane acrylate oligomers. The present work deals with kinetic studies and molecular characterization of the uncatalyzed bulk reaction of these two difunctional monomers. Back titration and H 1 ‐NMR are used to follow the r…
Abstract Composite materials were prepared utilizing whole carpet and LDPE. The addition of compatibilizers during processing was shown to provide an improvement in the mechanical performance of such materials. It is believed that the addition of a reactive compatibilizer to the system increases both the compatibility…
We have compared the magnitudes of reversible and irreversible polarization components of sol–gel-derived Nd3+- and Fe3+-doped PZT (53/47) thin films on platinized silicon substrates. Beyond the switching field, it was found that the reversible component of the polarization remains almost constant both for donor- (Nd3…
This letter presents a clear explanation of the electron emission mechanism of the high-resistivity N-doped diamond cathode. Due to the very low barrier to emission of electrons from the N-doped diamond conduction band into vacuum, electrons in the conduction band of diamond can establish an appreciable leakage curren…
We present experimental evidence of nanojunction structures explicitly observed after application of high electric fields on multiwall carbon nanotube arrays. The electric field as well as thermal effects result in carbon–carbon bond breaking and redeposition leading to nanojunction formation. The growth mechanism of…
The hysteresis area as a function of frequency of the time-varying external electric field—hysteresis dispersion—for ferroelectric Pb(Zr0.52Ti0.48)O3 is measured, and the Monte-Carlo simulation on the hysteresis dispersion for a model ferroelectric lattice is performed too. We demonstrate the scaling behavior of the s…
We fabricated an epitaxial Au/SrTiO3(001)/SrRuO3 (or CaRuO3)(001)/SrTiO3 (or LaAlO3)(001) heterostructure to investigate the effect of the strain on the epitaxial tunable dielectric thin films. SrTiO3 thin films showed very different dielectric properties depending on the bottom electrode with an opposite lattice mism…
Abstract In this article we report on the investigation of the dynamics of poly(vinyl alcohol) (PVA) and PVA‐based composite films by means of dielectric spectroscopy and dynamic mechanical thermal analysis. Once the characterization of pure PVA was done, we studied the effect of a nanostructured magnetic filler (nano…
Abstract p ‐Phenylenediamine (PPDA) homopolymer and its copolymers with 2,3‐xylidine (XY) were synthesized by oxidative polymerization using potassium persulfate as an oxidant in HCl medium at room temperature. The yield, intrinsic viscosity, and solubility of the polymers were significantly dependent on the monomer r…
Abstract This article reports on a comprehensive study of the reaction kinetics, particle morphology development, and polymer properties of impact polypropylene produced in gas phase with a TiCl 4 /MgCl 2 catalyst. Experiments were conducted over a range of copolymerization times, temperatures, monomer compositions, a…
Transport properties of various semiconducting zig-zag carbon nanotube Y junctions are studied for the investigations of rectification and switching. Our results indicate that such junctions, when symmetric, can support both ballistic rectification and/or the ballistic switching operating modes. Although structural sy…
The structural properties of high-quality (0001)ZnO/Al2O3 films grown by plasma-enhanced molecular-beam epitaxy are investigated by x-ray diffraction and transmission electron microscopy. The only defects encountered are threading dislocations with a density of 1010–4×1010 cm−2. Most numerous dislocations are pure-edg…
SrBi 4 Ti 4 O 15 single crystals were grown, and their dielectric and ferroelectric properties were investigated along the a(b) axis and c axis, separately. The dielectric permittivity at 1 MHz was 1900 along the a(b) axis at the Curie temperature of 520 °C. This value was ten times higher than that along the c axis.…
We demonstrate a large-area fabrication of hexagonally ordered metal dot arrays with an area density of ∼1011/cm2. We produced 20 nm dots with a 40 nm period by combining block copolymer nanolithography and a trilayer resist technique. A self-assembled spherical-phase block copolymer top layer spontaneously generated…
Piezoresponse scanning force microscopy measurements performed on lead zirconate titanate mesoscopic structures revealed a negative shift of the initial piezoelectric hysteresis loop. The shift is dependent on the size of the structure and is most probably due to the pinning of ferroelectric domains at the free latera…
In the temperature interval 300–773 K, ac and dc electrical measurements show a phenomenally large enhancement of the electrical conductivity of otherwise excellent insulator Al2O3 crystals when doped with magnesium impurities. The conductivity increases linearly with the concentration of hole-trapped [Mg]0 centers an…
This work deals with the analysis of peculiarities of formation of the hyperfine fields (HFF) at the Fe nuclei in disordered alloys metal- metalloid using the "first-principles" calculations. Some phenomenological models and justification of their usage for the interpretation of the experimental HFF distributions are…
Metamaterials are so-named to recognize and emphasize their purpose, which is to achieve material performance beyond the limitations of conventional composites. The holy grail of conventional composite design is to achieve an optimum combination of the constituent's properties without requiring that they react. Succes…