Materials Literature
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The fundamental mechanisms of a metal-dielectric transition are examined. The multiband theory of the metal-dielectric transition is reviewed, as based on realistic models of the band structure of a set of oxides and sulfides of the 3d-metals in which the transition is accompanied by structural and magnetic phase tran…
Abstract The general response of protein structures to mutations, insertions and deletions is conformational change. Comparisons of related proteins show that a large part of the polypeptide chain retains its basic folding pattern. This ‘core’ of the structures comprises major elements of secondary structure and resid…
The principal methods for the determination of the degree of charge transfer are examined and experimental data on the intermolecular distribution of electron density in charge-transfer complexes and radical-ion salts of the π–π are surveyed. The relation between the degree of charge transfer and the ionisation potent…
By use of depolarized laser relection microscopy, unique textural defects have been observed in thin tilted hexatic liquid-crystal films which result from their bond-orientational order. The temperature dependence of the bond-orientational elasticity can be deduced from these textural patterns and is in qualitative ag…
We have formed the icosahedral phase in ${\mathrm{Al}}_{86}$${\mathrm{Mn}}_{14}$, ${\mathrm{Al}}_{82}$${\mathrm{Mn}}_{18}$, and ${\mathrm{Al}}_{75.5}$${\mathrm{Mn}}_{20}$${\mathrm{Si}}_{4.5}$ alloys by the interdiffusion of elemental layers in the solid state. Annealing at 250-425\ifmmode^\circ\else\textdegree\fi{}C p…
We demonstrate the use of third harmonic generation as a probe of the bulk symmetry properties of semiconductors. Using 20 ns, 1.06 μm laser pulses we have applied this probe to structural diagnostics of (100) annealed and unannealed Si wafers implanted with boron and arsenic ions at dosages above and below the thresh…
Abstract A model based on geometrical crystal growth considerations is proposed for the deposition of the crocodilian, testudinian and avian eggshells. Ir each shell column, crystal deposition is initiated at a single location, from which growth fans out at all angles to the shell normal. In both co1citic and aragonit…
The energetics of icosahedral ordering in cholesteric liquid crystals are studied within the Landau mean-field approximation, in an attempt to describe the blue fog (blue phase III). We expand the free energy of a quasicrystalline phase in the high-chirality limit (coherence length much greater than pitch), and find t…
The angular distribution of light scattered by an extremely dilute birefringent lyotropic phase shows two well-defined Bragg peaks providing strong evidence of a true lamellar order (lamellae \ensuremath{\sim} 40 \AA{} thick and 6500 \AA{} apart in the diluent). The steric origin of the stabilization of this stacking…
Potassium dihydrogen phosphate (KDP) crystals were grown under the irradiation of ultraviolet light. The bulk laser damage threshold was improved to two to three times (15–20 J/cm2) compared to the case of crystals grown by conventional methods. Microbes such as germs and bacteria are frequently generated in the KDP s…
The spinel solid solutions ZnCr 2x Al 2-2x S 4 have been studied by means of neutron diffraction in the concentration range 0.85<or=x<or=1. For the pure compound (x=1), several powder samples with different heat treatments and a single crystal were studied. At T N (x=1)=15.5, T N (x=0.9)=14.5 and T N (x=0.85)=14…
Results of the electrocaloric effect (ECE) studies of Pb(Sc0.5Nb0.5)O3 ceramic in the temperature range from 320 to 400 K are reported. A great value (ΔTmax = 0.9 K) of the electrocaloric effect is observed. The temperature and field dependence of ECE is consistent with the presumption of a polar and nonpolar phase mi…
Spin echo NMR measurements on 159 Tb have been done in magnetically ordered state of the cubic Laves phase compounds Tb(Fe 1- x Co x ) 2 and Tb 0.8 Y 0.2 Fe 2 . Satellite structures observed in the compounds with x ≤0.2 are assigned to various Fe, Co configurations in the nearest neighbor shell. The resonance frequenc…
Lavas phase compounds (Y x Zr 1- x )Fe 2 have C15 structure, and are ferromagnetic. They absorb hydrogen under the condition of 1 atm, room temperature, to form hydrides (Y x Zr 1- x )Fe 2 H y . Hydrogen content y increases from O(ZrFe 2 ) to 4.2(YFe 2 ) with x continuously. The dependence of µ Fe and T c of hydrides…
Surface-enhanced Raman scattering spectra of p-nitrobenzoate on obliquely evaporated Ag films are presented. A surface anisotropy of the Raman enhancement for grazing evaporation angles was found.Received 24 December 1985DOI:https://doi.org/10.1103/PhysRevB.33.5917©1986 American Physical Society
We report measurements of the low-temperature specific heat of ${\mathrm{Li}}_{\mathrm{x}}$${\mathrm{NbS}}_{2}$, for 0\ensuremath{\le}x\ensuremath{\le}1. Samples were prepared by intercalating lithium into ${\mathrm{NbS}}_{2}$ in electrochemical cells. X-ray diffraction and electrochemical measurements show that stage…
The temperature dependences of NMR spin-echo spectrum and magnetic susceptibility have been measured in the quasicrystalline phase of Al 80 Mn 20 . Compared with the equilibrium crystalline (hexagonal) phase, the susceptibility shows a marked temperature dependence below about 100 K. The widely distributed and tempera…
Temperature dependence of specific heat at constant pressure, and temperature and hydrostatic pressure dependence of elastic constants have been measured on single crystals of black phosphorus. Elastic softening is observed in c 55 with decreasing temperature. The elastic constants c 11 , c 22 and c 33 increase with p…
We report what we believe to be the first observation of definite coherent directional relationship between a cubic \ensuremath{\alpha} phase and an icosahedral phase in rapidly quenched Al-Si-Mn. Electron-microscopic studies reveal that the set of three cubic orthogonal [001]-type directions are parallel, respectivel…
The electrical properties of the charge-density-wave compound blue bronze (${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$) have been investigated at several temperatures around T=4.2 K. A nonlinear current-voltage relationship was observed with an increase of the conductance by six orders of magnitude above a well-defined t…