Materials Literature
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Measurements of the spin-lattice relaxation time ${T}_{1}$ by the inversion-recovery technique are reported for two paramagnetic centers in quartz over a wide temperature range: from 1.3 to 250\ifmmode^\circ\else\textdegree\fi{}K for the ${{E}_{1}}^{\ensuremath{'}}$ center, and from 2 to 80\ifmmode^\circ\else\textdegr…
Sharp-line fluorescence of the ${\mathrm{V}}^{2+}$ ion in magnesium oxide and corundum has been studied at low temperatures, with and without a magnetic field. The excitation spectrum is used to determine the energy level scheme. The results are analyzed in terms of crystal field theory, and the vibrational structure…
For the ${(\mathrm{N}\mathrm{i}{\mathrm{F}}_{6})}^{4\ensuremath{-}}$ complex in KNi${\mathrm{F}}_{3}$ we have constructed molecular orbitals (MO) which are linear combinations of the ${\mathrm{Ni}}^{2+}$ and ${\mathrm{F}}^{\ensuremath{-}}$ Hartree-Fock atomic orbitals. These LCAO-MO, introduced by Van Vleck, are of th…
The three magnetic states which occur in the Cr-modified ${\mathrm{Mn}}_{2}$Sb system have been studied by measurements of magnetization, torque, and x-ray lattice cell dimension on single crystals. The exchange inversion transitions between magnetic states for a given composition are shown by x ray to be first order.…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation N. E. Wolff, R. J. Pressley; OPTICAL MASER ACTION IN An Eu+3‐CONTAINING ORGANIC MATRIX. Appl. Phy…
The fusion curves of several elements and III-V compounds crystallizing in the diamond/zincblende structure have been determined to 50, or sometimes 70, kbar by means of differential thermal analysis. The melting slopes are (in \ifmmode^\circ\else\textdegree\fi{}C/kbar); Si, -5.8 (lower bound); Ge, -3.8; InAs, -4.3; G…
A pattern of attack, qualitatively similar to groove pitting of irradiated fuel cladding, was produced in the laboratory. The relative susceptibility to attack of X-8001 alloy aluminum in comparison to 1245 alloy aluminum is in agreement with reactor experience. The remaining readily recognizable feature of in-reactor…
Pyrolytic graphite was cleaved in a high vacuum to obtain clean surfaces, and the secondary electron emission properties of these surfaces were determined. Pyrolytic graphite has a maximum secondary emission yield of 1.0 at 300-eV primary electron energy for electrons incident normal to the basal plane. The most proba…
Methods commonly used for reducing or for eliminating image distortion in the electron microscope image frequently cause inconvenience to the operator or are effective only over a limited range of magnification. In the present investigation previous calculations of Liebmann and Haine are extended in order to evaluate…
The solution spectra of tetraethyl ammonium salts of some complex halides of divalent iron, cobalt and nickel over the range 1000–20 000 cm-1 have been obtained. The positions of the various absorption bands can be correlated with transitions within the 3d shell of the metal ion but the relative intensities reveal the…
Abstract The potential, which a silver wire acquires in contact with Ag + ions in concentrated solutions of KCN, was studied potentiometrically. The solubility products or the instability constants of the following reactions have been calculated: equation image Normal potential values corresponding to the preceding eq…
It is shown in detail how the magnetoelectric effect depends quadratically on the spin-orbit interaction. The effect is discussed in Cr2O3 using the spin Hamiltonian for the cases of an applied field parallel and perpendicular to the crystalline c axis.
The intermetallic compound UFe2 is ferromagnetic. A considerable number of magnetization isotherms have been obtained from 200°K down to 4.2°K with applied field up to 14 000 Oe. The Curie temperature has been determined to be 172°K and the Bohr magneton number 1.02 per UFe2 molecule. Several hysteresis loops at diffe…
Abstract The acid‐catalyzed condensation of formaldehyde and aromatic nitrile has been investigated. Methylenebis( p ‐carboxyphenyl)amide was synthesized in 90% yield by the interaction of p ‐cyanobenzoic acid with formaldehyde under the influence of conc. sulfuric acid. Polycondensation of methylenebis( p ‐carboxyphe…
Abstract Urethane polymers comprise one of the most rapidly expanding areas of the organic chemical industry. Polyurethane production, estimated at about 100 million lb in 1960, is expected to rise to 500 million lb in 1965 and to have an ultimate potential in excess of a billion lb. The polymers are used in foams (fl…
Well-defined exchange splittings of the R lines of Cr3+ in Cr2O3 have been observed in absorption at low temperatures. The majority of the transitions originate on the lowest (Ms=−32) component of the A24 (ground) state and terminate on the four (exchange split) components of the two E2 levels. The lines show strong p…
Evidence has been found which suggests the existence of high‐temperature crystalline modifications of both zirconium carbide and tantalum carbide. The high‐temperature inversion in zirconium carbide, indicated by a sharp decrease in spectral emisivity, in electrical resistivity, and in density, was reversible. No perm…
An abrupt magnetic transition in MnSn2 was reported by Kouvel and Hartelius1 about one year ago. The salient features of the magnetic behavior are a smooth susceptibility maximum at 86°K and an almost discontinuous decrease in susceptibility at 73°K. At the suggestion of Kouvel, a neutron diffraction study was made to…
Abstract A study of the ultraviolet absorption spectrum of polyvinyl alcohol (PVA) was made. Spectral examination of the solvolysis products of vinyl acetate and 1‐methoxyvinyl ester copolymers shows unequivocally that the absorption bands in PVA at 225, 280, and 330 mμ are related to carbonyl‐containing structures. T…
The experimental and theoretical effects of magnetocrystalline anisotropy upon the magnetic first-order phase transition in the compound MnAs are here described. A 3°C orientation-dependent difference in the transition temperature is observed near 20 kOe for a single-crystal specimen. Anisotropy measurements using She…