Materials Literature
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Effects of x-ray irradiation combined with either bias voltage or bipolar electrical cycling were analyzed on three-dimensional ferroelectric capacitor arrays developed for highly reliable ferroelectric random access memories. Using dedicated experimental setup enabling in situ measurements, switching kinetics were fo…
A few compositions in the system CaCu 3 Ti 4- x Sn x O 3 (0≤ x ≤1.0) were synthesized by solid state diffusion controlled thermochemical process. Powder X-ray diffraction patterns of all the compositions show that these compositions are single phase solid solution. All the samples have cubic crystal structure similar…
Chapter 10.1 treats the geometric and group-theoretical aspects of both crystallographic and noncrystallographic point groups. The central part of the chapter is an extensive tabulation of the 10 two-dimensional and the 32 three-dimensional crystallographic point groups, containing for each group the stereographic pro…
ZnO nanorod-based single quantum well heterostructures were fabricated in a two-step process. Nanorods were first grown using vapour transport. Subsequently, high-quality ZnO/Zn 0.85 Mg 0.15 O heterostructures were grown on the nanorods using molecular beam epitaxy. The nanorods are well aligned along the c -axis of Z…
Abstract Single‐phase gels with compositions 3Al 2 O 3 ·2SiO 2 and 2Al 2 O 3 ·SiO 2 were prepared by gelling mixtures of aluminium nitrate and tetraethylorthosilicate. Gels were fast heated at different temperatures between 900°C and 1600°C. The phase transformation and microstructural changes of both mullite precurso…
We present a quantitative picture of the separation of star polymers in a solution where part of the volume is influenced by a porous medium. To this end, we study the impact of long-range-correlated quenched disorder on the entropy and scaling properties of f-arm star polymers in a good solvent. We assume that the di…
The energy band gap (Eg) of colloidal InGaP∕ZnS core/shell nanocrystals is investigated by using the optical absorption and the photoluminescence techniques. While the photoluminescence spectra exhibit a strong emission, the optical absorption spectra show a very weak excitonic absorption. From Eg values estimated fro…
This chapter deals with electron diffraction and imaging in the transmission geometry at kilovolt and higher beam energies for the purposes of crystal structure determination. Techniques such as low-energy electron diffraction, gas electron diffraction and reflection electron diffraction are not considered. Following…
The Patterson function is a phaseless Fourier synthesis of diffraction intensities that corresponds to an autocorrelation of electron densities in a crystal cell. Prominent non-origin peaks in a Patterson function represent interatomic vectors; deconvolution of this information can be used to locate heavy atoms, known…
The ubiquitous static friction (stiction) and adhesion forces comprise a major obstacle in the manipulation of matter at the nanoscale (Falvo et al 1999 Nature 397 236; Urbakh M et al 2004 Nature 430 525). In this work it is shown that a surface coated with vertically aligned carbon nanotubes—a nanotube forest—acts as…
The compatibility of low-dimensional thermoelectric materials in forms such as thin films and nanowires for use in thermoelectric coolers is examined. First-order thermoelectric theory predicts that the cold and hot junction temperatures of a thermoelectric circuit are governed solely by the nondimensional figure of m…
Zinc-blende-structured MnAs epitaxial films were grown on GaAs (100) substrates with InAs buffer layer. The resistivity and the Hall resistance behavior at various temperatures indicate that the MnAs thin film is half-metallic in nature. A MnAs∕GaAs∕MnAs spin-valve structure, fabricated utilizing half-metallic MnAs th…
Abstract Stannous oxide (SnO 2 ) thin film is one of the most widely used n‐type transparent semi‐conductor films in electronics, electro‐optics and solar energy conversion. By achieving controlled non‐stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO 2 thin films. Dy a…
Oxygen atom adsorption onγ-TiAl(111) surface is studied using first-principles approach.The adsorption site with more Ti atoms as its nearest neighbors on the surface layer is found to be preferred.Adsorption energy differences between different adsorption sites become smaller with increasing of oxygen coverage.Electr…
Of the processes that reduce the intensity of X-rays passing through matter, photoelectric absorption, scattering and extinction are important for the X-ray wavelengths used in crystallography. This chapter discusses each in turn. Different kinds of absorption corrections are described and parameters for use in calcul…
Abstract The molecular symmetry of all the existing organic ferroelectrics was analyzed with an intention to develop a criterion to search for new low molecular weight organic ferroelectric. We present here a summery of the analysis; it is conclude that in order to exhibit ferroelectricity in crystalline state the mol…
Solid state reaction silicon nanocrystals (Si nc’s) of an average size of 10nm have been synthesized. Charge transport characteristics have been investigated as a function of temperature and voltage. From 305to400K, it is found that space-charge-limited current (SCLC), with an exponential distribution of trapping stat…
This is version 2.0.11 of the macromolecular CIF dictionary (mmCIF), dated 300 May 2007. The philosophy behind this dictionary and the history of its development are described in Chapter 8.1. A detailed commentary on the use of the dictionary is given in Chapter 3.11.
It is shown that reduction of the symmetry of the shape of almost spherical nanocrystals to that of a three axial ellipsoid or lower leads to a splitting of the exciton radiative doublets into linearly polarized components. The splitting is a result of a combined action of the distortion of the boundary conditions and…
We introduce a mesoscale technique for simulating the structure and rheology of block-copolymer melts and blends in hydrodynamic flows. The technique couples dynamic self-consistent field theory with continuum hydrodynamics and flow penalization to simulate polymeric fluid flows in channels of arbitrary geometry. We d…