Materials Literature
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Ablation of diamond by short UV pulses is reported. The ablation threshold for 500 fs pulses at 248 nm was found to be 0.6 J/cm2 (equal to a peak intensity of 1.1 TW/cm2). Intensity-dependent transmission measurements from low intensities to 100 GW/cm2 showed that two-photon absorption is the dominant nonlinearity in…
The third-order optical nonlinearity χ(3) of porous silicon has been measured using the Z-scan technique. Intensity dependent absorption was observed and attributed to a resonant two photon absorption process. The real and imaginary parts of χ(3) have been measured at 665 nm and found to be 7.5×10−9 esu and −1.9×10−9…
The structural behaviour of copper(I) iodide, CuI, has been investigated between room temperature and its melting point (T M =878 K) using neutron powder diffraction. Detailed measurements have been made in the vicinity of the two known structural phase transitions gamma to beta and beta to alpha , which are observed…
We report x-ray photon correlation spectroscopy studies of the static structure factor and dynamic correlation function of a gold colloid dispersed in the viscous liquid glycerol. We find a diffusion coefficient for Brownian motion of the gold colloid which agrees well with that extrapolated from measurements made wit…
Zirconia single crystals, partially stabilized with 6.6 mol% Y2O3, are annealed at 1600°C for 50 h. These crystals, which were investigated by high voltage electron microscopy, contain few relatively large precipitation colonies and many small precipitates regularly arranged in a tweed structure. The colonies consist…
Basal plane stacking disorder, delamination cracks, misorientation bands and low angle (0001) twist boundaries are observed by high resolution transmission electron microscopy in small, highly defective, boron nitride inclusions introduced unintentionally in silicon nitridesilicon carbide composites during the fabric…
The magnetic properties and phase transitions of 1T-${\mathrm{TaS}}_{2}$ and 1T-${\mathrm{Fe}}_{0.07}$${\mathrm{Ta}}_{0.93}$${\mathrm{S}}_{2}$ have been studied in the interval of 1.5--300 K and over the range of 100 Oe--60 kOe. Experimental results show that at high temperatures the compounds are in a diamagnetic sta…
A current controlled, high speed, near ideal electrical switching has been observed for the first time in microwave prepared AgI based fast ion conducting glasses. The switching is found to be memory type, which is not reverted to OFF state by the application of a resetting current pulse. The threshold fields exhibit…
The electronic spectra of \ensuremath{\alpha} and \ensuremath{\beta} solid ${\mathrm{O}}_{2}$ were calculated in a full many-body approach for a cluster consisting of four ${\mathrm{O}}_{2}$ molecules with periodic-boundary conditions. By including only the partially occupied \ensuremath{\pi} orbitals (16 spin orbital…
Ferroelectric 180° domain structures of CsH 2 PO 4 (CDP) and (NH 2 CH 2 COOH) 3 ·H 2 SO 4 (TGS) have been observed in unelectroded b plates using the secondary emission mode of a scanning electron microscope (SEM). It is found that a lamellar domain structure is formed in CDP. The lamellar structure shows the fine per…
The structure and magnetic properties of RFe12−xMox series and their nitrides with R=Y,Gd,Nd and x=0.8,1.0,1.5,2.0,2.5 have been studied by x-ray-diffraction and magnetic measurements. It is found that with the increment of Mo content x, the lattice parameters increase, whereas the saturation magnetization, Curie temp…
The electronic energy band structures for BaNiS 2 and BaCoS 2 , which are considered as highly correlated layered structure systems, have been calculated by using the scalar-relativistic full-potential linearized augmented plane wave (FLAPW) method within the local-density approximation. The result of the calculation…
The structures of di(acetone)tetrakis(mu 3,5-dinitrobenzoato-kappa 2 O:kappa O')hexakis(mu-3,5-dinitrobenzoato-kappa O:kappa O')-di-mu 4-oxo-di(pyridine)tetramanganese(II)dimanganese (III)-acetone-diethyl ether (1/2/2), (1), and tetrakis(acetonitrile)tetrakis(mu 3-benzoato-kappa 2 O:kappa O')hexakis(mu-benzoato-kappa…
We report the observation of nonlinear voltage response both to dc current and to unipolar current pulses in the commensurate charge-density-wave (CDW) state of the molecular conductor (perylene${)}_{2}$Pt(mnt${)}_{2}$ (mnt=maleonitriledithiolate). At T=4.2 K, two nonlinearities in the I-V curves are observed at ${\ma…
A study of quantized excitons in CuCl epitaxial thin films is reported. Film thicknesses (L) that are much smaller than the photon wavelength (\ensuremath{\lambda}) in the medium (\ensuremath{\sim}160 nm), but larger than the exciton Bohr radius ${\mathit{a}}_{\mathit{B}}$ (\ensuremath{\sim}0.7 nm), are considered her…
The coercivity mechanism of Nd-Fe-B sintered magnets is investigated using a continuously varying model for a single variable K. The results show that the starting field Hs (which includes the critical field H0 and the expanding field He) is greater than the nucleation field Hn and is the main element that controls th…
Luminescence characteristics in Er3+-ion activated, Yb3+-ion sensitized infrared upconversion materials have been investigated, especially for their energy back transfer processes from Er3+ to Yb3+ ions. Decay characteristics of Er3+ ion green emission have been examined in various fluoride crystals and fluoride glass…
Nucleation of oriented diamond particles on cobalt substrates has been achieved by a multistep, hot-filament chemical vapor deposition process, which involves seeding, annealing, nucleation, and then growth. The substrates were seeded with either diamond powders, graphite powders, or gaseous carbon species. Scanning e…
Antiferromagnetism has been found in a Heusler alloy Fe2VSi from measurements of electrical resistivity, magnetic susceptibility and Mössbauer spectroscopy of 57Fe. The Néel and Weiss temperatures are 123 K and -212 K, respectively. The magnetic moment of an Fe atom estimated from Mössbauer spectrum splitting is 0.22…
Abstract An adaptation of the fracture toughness test method, the J ‐integral technique, is described within the general framework of polymer fracture behavior. It is shown that there is a strong interaction between different morphological parameters in the way they affect the fracture behavior of isotactic polypropyl…