Materials Literature
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Thin films play a dominant role in modern technology. They appear as vital elements in integrated circuits as well as superconducting elements and solar energy conversion structures. Thin films are used both as active structures of precisely controlled thickness and area, and passive structures for connection to, or i…
The effective resistivity is calculated for a simple cell structure by means of the Boltzmann equation. In less heavily deformed metals the cell structure has only a negligible effect on the residual resistivity. In heavily deformed metals the observed DMR is in the same order of magnitude as that arising from the pre…
Nominally undoped YAG crystals become brown, when they are irradiated with hard rays at room temperature (RT). Investigations of absorption and fluorescence are discussed. Two fundamental types of coloration-independent fluorescence can be correlated with two fundamental types of coloration of nominally pure crystals…
Mössbauer spectra of several samples of the spinel system Fe3−xAlxO4 with 0 ≦ x ≦ 1.5 were obtained at room temperature and analysed. For x < 0.9 the spectra of the samples show several Zeeman patterns, which are attributed to tetrahedral and octahedral iron cations. With x > 0.9, the spectra show no theoretical Zeema…
The crystal structure of (CH3NH3)2MnCl4 is determined by neutron diffraction at 404 and 293 K in order to obtain a microscopic description of the second-order structural phase transition at 393.8 K. The high temperature phase has a disordered K2NiF4-type structure (I4/mmm). The ordered structure at room temperature (A…
A new method is proposed for the analysis (vacancy or interstital) of dislocation loops by means of the so-called inside-outside contrast. A simple and straightforward recipe is developed which is applicable in the same manner to loops of edge and of non-edge type irrespective of the loop orientation within the transm…
(CH3NH3)2CdCl4 is found to be isotructural at room temperature with (CH3NH3)2MnCl4 having the orthorhombic space group Cmca. A high temperature phase transition to a tetragonal phase could not be observed because of a decomposition slightly above 383 K. Two low temperature phase transitions are detected by means of DT…
After a comparison of the β-, ϵ-, γ-, and δ-type GaSe crystal structures, the different interlayer interactions are discussed. New values for the intralayer interatomic distances Se–Ga = 2.463 (15) Å, Ga–Ga = 2.457 (18) Å, and the interlayer distance Se–Se = 3.880 (15) Å are proposed. These are mean values for the δ-t…
High pressure optical measurements have been made on two spiropyrans dissolved in films of polystyrene (PS) and polymethyl methacrylate (PMMA). Three types of studies were made. (1) In the pressure region 30–140 kbars we observed pressure induced coloration (piezochromism) which was independent of time, rate of pressu…
Single crystals of FexTaS2 (x≈0.28) are metallic, ferromagnetic (Tc=73±5 °K), and have a large coercive force of 55 kOe at 4.2 °K. Mössbauer measurements show the iron to be high-spin Fe2+, with a distribution of hyperfine fields at low temperatures. Electron microscopic observations, together with these results, sugg…
The optical absorptivity of crystalline Pd was measured at 4.2 K between 0.15 and 4.4 eV. The data were Kramers-Kronig analyzed to determine the dielectric functions and the optical conductivity, $\ensuremath{\sigma}$. A strong maximum was observed in $\ensuremath{\sigma}$ at 0.46 eV followed by a broad shoulder near…
Kumar and Sorbello have expressed the effective force on an ion in electromigration in terms of a response function, which is evaluated here by the method of quantum field theory. Formulas for the force are derived for the jellium model and for a crystal lattice. Some physical insight can be gained by viewing previous…
We study the effect of interchain coupling on the Peierls transition temperature ${T}_{P}$ for a model with a nonplanar Fermi surface. Using the standard electron-phonon coupling, we show that the soft mode which causes the transition should have a wave vector ${q}_{0}=(\frac{\ensuremath{\pi}}{a}, \frac{\ensuremath{\p…
We have formed large-grained essentially free-standing crystals of solid argon. Subsequent in situ measurements of the thermal conductivity $\ensuremath{\kappa}(T)$ were made by a linear-flow method, covering a temperature range from the triple point, 83.8 K, to liquid-He temperatures. The low-temperature data were hi…
The absolute electron affinities of pi charge transfer complex acceptors have been examined and the ’’best’’ values have been chosen. All of the results obtained by the magnetron method, including the estimates for hexafluorobenzene and tetracyanoethylene, were accepted. However, the magnetron results for anthraquinon…
In mol\`ecular crystals and other crystals with internal degrees of freedom, the fundamental measures of anharmonicity are generalized mode Gr\"uneisen parameters. These are derivatives of the frequency with respect to external or internal strain, with all other external and internal strains held constant. Zallen's vi…
The free-ion energy level scheme of Cm3+ (aquo) to ∼40 000 cm−1 was determined. Energy level assignments were made based on the correlation between observed band intensities and those calculated using the Judd–Ofelt theory. Use of an expanded set of effective operators provided the basis for computation of free-ion en…
Very accurate measements of the photoemission yield have been performed on the (111) face of silicon as a function of photon energy in the threshold region down to the ${10}^{\ensuremath{-}10}$ range. Using a set of differently doped samples cleaved in ultrahigh vacuum, one can distinguish between surface- and bulk-st…
Drift velocities for holes in high-purity Si were measured for fields between about 3 and 5\ifmmode\times\else\texttimes\fi{}${10}^{4}$ V/cm and temperatures between 6 and 300\ifmmode^\circ\else\textdegree\fi{}K for the crystallogrphic directions $〈100〉$, $〈110〉$, and $〈111〉$. The Ohmic mobility is theoretically inter…
Abstract The homogeneous rate theory of void growth is extended to include the possibility of forming vacancy loops when the irradiation produces cascade damage. The analysis provides a basis for understanding and correlating the relative swelling generated during electron; heavy ion and fast neutron irradiation. In o…