Materials Literature
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The low and high temperature DC and AC conductivities of As-Se-Te glasses have been studied with different Se:Te ratios. The transport behaviour has been discussed in terms of known transport mechanisms. The composition dependence of the conductivities are discussed in terms of known structures. The transport among ex…
Abstract Elektronenspektroskopische Untersuchungen zeigen, daß der aus dem Chloro‐tetraphenylporphinato‐Fe(III)‐Komplex (I) dargestellte Bis‐[imidazol]‐Komplex (II) durch verschiedene Basen wie Tetrabutylammoniumhydroxid,K‐tert.‐butoxid oder K‐imidazolat am Imidazol unter Bildung der Produkte (III) und (IV) deprotonie…
We present direct measurements of the layer rigidity in a smectic-$A$ liquid crystal, 4\ensuremath{'}-$n$-octyloxy-4-cyanobiphenyl. For low normal to the layers, the instantaneous induced stress is elastic and gives $B=0.8\ifmmode\times\else\texttimes\fi{}{10}^{7}$ cgs units at 60\ifmmode^\circ\else\textdegree\fi{}C.…
Abstract The results of a computer simulation of the structure of periodic grain boundaries between twin related crystals of aluminium are described. An interatomic potential derived on the basis of pseudo-potential theory was used. The algorithm employed allows simultaneous local atomic relaxation and rigid body tran…
We demonstrate that dimerized organic linear-chain conductors afford an unambiguous experimental determination of symmetry-allowed electron-molecular-vibration coupling constant.Received 25 July 1977DOI:https://doi.org/10.1103/PhysRevLett.39.1359©1977 American Physical Society
Complex investigations are made (neutron diffraction study, high temperature X-ray analysis, dielectric measurements at low and superhigh frequency ranges, resonance (ESR and Mössbauer effect) and magnetic measurements) on the known compounds A2BReO6 (A = Ba, Sr; B = Li, Mg, Ca, Mn, Fe, Co, Ni) and under high pressure…
The role of electron concentration in the formation and stabilisation of inversion anti-phase domain (IAPD) arrays in γ-brass type phases is determined by a study of γ-phases in the Ni-Zn, Co-Zn, and FeZn systems. IAPD arrays form in Ni-Zn alloys in the range Ni-75 at%Zn to Ni-80 at%Zn but are not observed in the Co-…
Structural changes and deformation processes acting during superplastic flow of a magnesium alloy (Mg + 1.5% Mn + 0.3% Ce, grain size Do ≈ 10 μm) in different regions of the σ-f(epsi;) curve are studied by a combination of techniques. It is experimentally established that the superplastic deformation of the alloy occu…
Studies of optical absorption and luminescence were carried out on CdCl 2 -CdBr 2 solid solutions in the whole concentration range. Three emission bands were observed in the regions of 2.1∼2.3 eV (Y-emission), of 2.4∼2.7 eV (G-emission) and of 3.2∼3.6 eV (UV-emission). When the concentration of CdBr 2 increases, the U…
The effect of pressure to 140 kbar has been measured on the room-temperature luminescent properties of some sodium and potassium halides doped with ${\mathrm{Cu}}^{+}$ and ${\mathrm{Ag}}^{+}$. The properties studied include peak location, peak half-width, and luminescent lifetime. A signal-averaging luminescent decay…
We have identified serious errors in a previously published assignment of the ir-active phonons for the $\ensuremath{\alpha}$-corundum structured crystal ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$. We have measured the ir-reflectance for the two principal polarizations, $\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}\ensu…
We have measured the linear and nonlinear susceptibilities of several mixed rare earth molybdates Ln2xGd2(1−x)(MoO4)3, where Ln is Nd, Sm, Gd, Tb, Ho, Yb. We conclude that the major part of the nonlinear optical properties is due to the MoO4 tetrahedra orientation and to the Mo–O bond hyperpolarizability. Extrapolated…
The Raman spectrum of $1T\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{Se}}_{2}$ has been studied for $2<T<480$ K. Changes in the Raman spectra have been observed which are correlated with the 473-K phase transition from the commensurate charge-density-wave (CDW) state to the incommensurate CDW state. The temperatu…
Clean cleaved ($1\overline{1}00$), (0001), and ($000\overline{1}$) surfaces of ZnO have been studied by electron energy-loss spectroscopy with primary energies ${E}_{0}$ between 35 and 100 eV. Differences between the nonpolar ($1\overline{1}00$) and the polar (0001) surfaces can be explained by the optical anisotropy…
The phase transitions of the charge density wave (CDW) state in 1T-TaS 2 are studied both theoretically and experimentally. The positions and intensities of the fundamental and third-order harmonic of the CDW are determined by X-ray diffraction. In order to understand the successive phase transitions, a theory is pres…
Detailed measurements of the specific heat and resistivity have been made on samples of $2H\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{Se}}_{2}$ and $2H\ensuremath{-}\mathrm{T}\mathrm{a}{\mathrm{S}}_{2}$ near their charge-density-wave phase transitions. Because the crystal quality of $2H\ensuremath{-}\mathrm{T}\mathrm{…
The phenomenon of ruby laser-induced breakdown in liquids is investigated by high-speed holography. The advantage of using holography instead of ordinary photography lies in the possibility to easily suppress the bright white light emitted during the breakdown process. This light constitutes an incoherent background o…
A generalized model of multiple trapping from a band of extended or localized states is used to study timedependent charge transport in amorphous solids. The model differs from a conventional multiple-trapping model by including a distribution of trap release rates for a constant trap energy. An extensive analysis of…
The effect of pressure on atomic positions and lattice parameters is determined for trigonal Se under pressures from 0 to 86 kbar and for trigonal Te from 0 to 40 kbar by single-crystal x-ray diffraction using a diamond anvil high-pressure cell in a standard precession camera. The structural data confirm the lattice-d…
Starting with the 'family tree' which shows the group-subgroup relations between the various structural phases of perovskite-type layer materials with organic ions, the symmetry types of the lattice vibrations and, for some selected cases, the symmetry coordinates are derived by standard group theoretical methods. Spe…