Materials Literature
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Using the common polarization-potential tensors and the common refractive-index-dispersion parameter which characterize the electro-optical and nonlinear optical properties of all oxygen-octahedra ferroelectrics, we analyze in detail the device behavior of electro-optic modulators, light deflectors, and optical second…
The problem of averaging fourth-rank tensors with texture describing weight functions has been solved for orthotropic physical symmetry and for orthorhombic crystal symmetry. The results are presented in tabular form. The procedure for extending the tabular results to tetragonal, hexagonal, and cubic crystal symmetrie…
Measurements of neutron scattering from an SrTiO 3 crystal have been carried out in the temperature range from 4.5°K to 300°K. The integrated intensity of inelastically scattered neutrons due to excitation of the soft optical phonon was observed at various reciprocal lattice points at room temperature. The structure f…
Neutron diffraction patterns for vitreous germania, synthetic vitreous silica and radiation-damaged synthetic silica have been obtained to 18 Å -1 . With the use of a special resolution function the results have been analysed to produce `radial distribution functions' free of truncation error ripples. The function for…
A microscopic tensor theory of the electro-optical and nonlinear optical effects in oxygen-octahedra ferroelectrics is presented. The theory stresses the importance of the basic BO6 octahedron building block in this class of materials. This common structural unit leads to similarities in band structure and similaritie…
Reflectivity measurements on dilute gold-iron alloys by a new method are reported. There is clear evidence that the band gaps change steadily on alloying. In the region 3 to 6 eV additional absorption growing nonlinearly with concentration suggests that the impurities are interacting with each other.
Crystals of CdGeO(3) grown at a pressure of 65 kilobars are tetragonal and have an ordered, garnet-like crystal structure with cadmium occupying the dodecahedral and octahedral sites, and germanium the octahedral and tetrahedral sites. The crystal structure (a = 12.406 +/- 1 angstroms, c = 12.256 +/- 1 angstroms, and…
Two-component cholesteric liquid crystal films have been observed to exhibit a remarkable structural dependence on composition. There is evidence that the relationship of color and temperature in these films is connected with this dependence.
Hall-effect, electrical-resistivity, and magnetic-susceptibility measurements have been made on polycrystalline specimens of nickel-copper alloys. The temperature range covered is 100 to 700\ifmmode^\circ\else\textdegree\fi{}K. The spontaneous Hall coefficient ${R}_{p}$ in the paramagnetic region has been separated ou…
This paper is concerned with the measurement and interpretation of the variations in the quantum efficiences and lifetimes of four of the Er3+ fluorescing levels in the 1%–10% concentration range in SrF2 at the three fixed temperatures 300°, 70°, and 4.2°K. The interpretation has centered on the identification of the…
Size-dependent deviations from Matthiessen's rule have been observed from 1.3 to above 40\ifmmode^\circ\else\textdegree\fi{}K in thin foils and fine wires of aluminum. These deviations are consistent, in the regions of overlap, with data published by other investigators. The deviations are shown to be inconsistent wit…
Optical and acoustic branches of chain vibrations of polyethylene glycol were treated by the use of the intrachain force field previously refined. From dispersion curves (frequency versus phase difference), the frequency distribution weighted by squared amplitudes of hydrogen nuclei was calculated, and inelastic therm…
SCOPUS: ar.j
At 77 K photoluminescence from nominally pure, 0.05% Sm-doped and 0.005% Cr-doped SrTi${\mathrm{O}}_{3}$ gives identical spectra in the infrared (I.R.) with an intensity ratio of 1:20:400, respectively. In undoped and Sm-doped specimens, the intensity of emission is vanishingly weak at 4 K, in contrast to Cr-doped SrT…
An analysis has been made of the optical absorption edge and reflectivity spectrum of single-crystal tellurium. Transmission measurements, using polarized light, were made between 10 and 300\ifmmode^\circ\else\textdegree\fi{}K covering a range of absorption coefficient from 0.4 ${\mathrm{cm}}^{\ensuremath{-}1}$ to 5\i…
The optical absorption coefficient of synthetic single crystals of the garnet ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ has been measured from photon wave numbers of 10 to 55 000 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 300\ifmmode^\circ\else\textdegree\fi{}K. The wave-number range 10 to 900 ${\mathrm{cm}}^…
The spectral distribution of the thermoluminescent glow peaks at 155, 206, and 333\ifmmode^\circ\else\textdegree\fi{}K and the room-temperature phosphorescence have been measured in Ca${\mathrm{F}}_{2}$: ${\mathrm{Ho}}^{+3}$ following x irradiation. The emission comprises about sixteen lines between 5300 and 5600 \AA{…
The metamagnetic (spin-flop) transition is studied in single crystals of Fe${\mathrm{Cl}}_{2}$ and Fe${\mathrm{Br}}_{2}$ using the M\"ossbauer effect and external magnetic fields up to 40 kG. From the changes which take place in the $m=\frac{1}{2}\ensuremath{\rightarrow}{m}^{*}=\frac{3}{2}$ and $m=\ensuremath{-}\frac{…
The ferroelectric properties of Rochelle salt have been studied by means of two new techniques based on the ${\mathrm{Na}}^{23}$ NMR. In the first technique, the separation between a pair of ${\mathrm{Na}}^{23}$ quadrupolar satellites is used as a measure of the spontaneous polarization of the crystal. Using this meth…
The velocity and attenuation of ultrasonic shear waves have been investigated at temperatures above ${T}_{C}={121.8}_{2}\ifmmode^\circ\else\textdegree\fi{}$K in single-crystal KDP. An elastic Curie-Weiss law, $({{s}_{66}}^{E}\ensuremath{-}{{s}_{66}}^{P})=\frac{D}{(T\ensuremath{-}{T}_{C})}$, is obtained with an elastic…