Materials Literature
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Strong intensity oscillations have been found in RHEED during epitaxial growth at 77 K. This temperature is too low for thermally activated diffusion and establishes that the deposited atom uses its latent heat of condensation to skip across the surface, preferentially coming to rest at growing island edges, to achiev…
By using a simple Hamiltonian of a combined crystal field and exchange field model good theoretical fits are made to the observed rare earth anisotropy constants K in a wide temperature range and the correct values of the spin reorientation temperature in R2Fe14B (R = Sm, Er, Tm, and Yb) are reproduced. The obtained c…
The stability of the transmission response of a tripole FSS as the angle of incidence is increased from 0° to 70° is compared with that for a surface using a three-dimensional version of the element, a calthrop. For TM incidence the drift in frequency of the reflection resonance is 10% for the tripole, but only 2.5% f…
A series of samples of the system Co1−xZnxFe2O4 (x = 0, 0.3, 0.4, 0.6, 0.8, and 1) are prepared by the usual ceramic technique. X-ray analysis shows that they are cubic spinel (single phase). The lattice parameter, theoretical density Dx, bulk density D, and the porosity P are measured for the samples. Thermopower and…
Emission and excitation spectra of the Mn 2+ ion in the SrS:Mn 2+ and SrS:Pb 2+ , Mn 2+ phosphor are investigated at various temperatures. The analysis of the excitation spectra of the Mn 2+ emission band leads to the Racah parameters B =712 cm -1 , C =3352 cm -1 and the crystal field parameter D q =576 cm -1 with the…
The electrical resistivity and the Hall coefficient of the layered compound ZrSe 2 and HfSe 2 grown by iodine vapour transport method have been measured. High anisotropy in electrical resistivities has been found for these compounds. The Hallmobility exhibits a temperature dependence of the form µ∝ T -1.6 in ZrSe 2 as…
An ab initio molecular-orbital study of the dissociation energy of boron monohydride of (BH) using quadratic configuration interaction and a large basis set is presented. The results suggest that the commonly accepted value for the dissociation energy Do of BH of 78.9 kcal/mol may be low by about 3– 4 kcal/mol.
A critique is given of classical models of depinning and transport by sliding charge-density waves (CDW) in quasi-one-dimensional metals. A considerable body of evidence supports a theory based on quantum tunneling over macroscopic distances, particularly on ${\mathrm{NbSe}}_{3}$ and ${\mathrm{TaS}}_{3}$. No sound pre…
Fermi-Dirac statistics have been applied to semiconducting diamond layers doped with boron by means of ion implantation. Suitable limiting equations could be derived to describe the resistance-temperature behavior which relates to acceptor activation and also to hole creation in the valence band by means of compensati…
The high-temperature sequence of phase transitions in ${\mathrm{LiKSO}}_{4}$ has been investigated by means of infrared reflectivity, Brillouin scattering, and electrical measurements. Results show the strong correlation between the lithium-ion mobility and the reorientational motion of the sulfate groups. The sulfate…
The melting curve of ice VIII near 25 kbar, which has a positive slope, has been estimated from various thermodynamic data and extrapolated approximately to 60 K at zero pressure. When ice VIII is heated from 77 K and ambient pressure it should, therefore, ‘‘melt,’’ presumably below the glass transition. It has been s…
The adhesion of human and rabbit platelets to collagens and collagen-derived fragments immobilized on plastic was investigated. Adhesion appeared to be independent of collagen conformation, since similar attachment occurred to collagen (type I) in monomeric form, as fibres or in denatured state. The adhesion of human…
Effects of the hybridization between the 4 f and valence band states on the multiplet structures in La 3 d and 4 d core X-ray photoemission spectra (XPS) are discussed for LaF 3 , LaCl 3 , and La 2 O 3 on the basis of the Anderson model considering the multiplets arising from the interaction between a 4 f electron and…
The electronic structure of cubo-octahedral and icosahedral ${\mathrm{Au}}_{13}$ clusters has been investigated by the self-consistent-field molecular-orbital Dirac scattered-wave method. Double-point-group--symmetry considerations indicate that the icosahedral cluster will undergo static Jahn-Teller distortion, while…
The initial stages of magnesium oxidation are investigated by high-resolution electron-energy-loss spectroscopy. Two species (magnesium oxide and chemisorbed oxygen) are simultaneously detected from their vibrational bands even for minimal oxygen exposures. The evolution of the surface oxide can be quantitatively desc…
There is a considerable disagreement in the literature on the description of lifetime effects arising from core-valence transitions in solids. We calculate here Auger and radiative widths of shallow core levels in Li, Be, Na, Mg, and Al with use of principles consistent with dynamical theories of secondary-emission pr…
The structural characteristics of Sr1−x Lax TiO3+δ (0≤x≤0.4) at 1400 °C have been investigated as a function of ambient oxygen partial pressure. A modified Rietveld pattern-fitting structure-refinement program [H. M. Rietveld, J. Appl. Crystallogr. 2, 65 (1969)] was used to determine the nature of the distortions of t…
A new electron trap, labeled ED1, with an activation energy of 0.68 eV has been found to appear in the deep-level transient spectroscopy spectrum of n-type GaAs crystals as a result of their plastic deformation at 400 °C. The trap has been systematically investigated taking into account broadening of its energy level.…
An experimental study of the temperature- (T-) dependent dc and audio-frequency conductivity (\ensuremath{\sigma}) as a function of protonation level (0.0\ensuremath{\le}x\ensuremath{\equiv}[${\mathrm{H}}^{+}$]/[N]\ensuremath{\le}0.08) of emeraldine polymer is presented. The dc conductivity varies from ${10}^{\mathrm{…
Lead zirconate-titanate (PZT) thin films with tetragonal and rhombohedral structures have been successfully grown with good epitaxy on MgO single crystals and on [100]-oriented platinum thin films by rf-magnetron sputtering. The PZT films were obtained by using sputtering targets with compositions of Pb(ZrxTi1−x)O3, w…