Recent Advances in Science and Technology of Materials: Volume 1

ISBN-13: 9781468430233 / Angielski / Miękka / 2012 / 420 str.

Adlai Bishay

Opis

If an ion in a crystal is replaced by an impurity ion with a different charge, compensation for the charge difference must be accomplished. This is usually done by an intrinsic defect, i. e. a lattice vacancy or interstitial host ion, in such a way to balance the excess or deficit of charge. The introduction of cation vacan cies along with divalent cation impurities in alkali halides is a familiar example. If these crystals are carefully annealed, nearly all of the compensating defects migrate to the impurity ions to form impurity-defect complexes. It is the behavior of these complexes that are the principal concern in this paper. Almost invariably such complexes are dipolar in character, and when subjected to an electric or mechanical stress field, they will tend to realign to an orienta tion of lower energy provided the thermal activation is sufficiently great. If the complex consists of an impurity-vacancy couple, re orientation may occur either by the vacancy moving around the impu rity or by an exchange of positions of the partners. In general the activation energy for these two distinct reorientation paths is different. If the complex consists of an impurity-interstitial couple, interchange of positions is unlikely and reorientation is considered to occur exclusively by the motion of the interstitial around the vacancy."

Spis treści

of Volume 1.- Defects in Solids.- Kinetics of Defect Formation in Alkali Halides at Helium Temperatures.- Relaxation of Impurity-Defect Complexes in Fluorite Crystals.- Intrinsic Point Defects in Oxides with the Rutile Structure.- The Capture of Electrons by Negatively Charged Impurity Atoms in n-Type Germanium.- Radiation Defects in Heavily Irradiated GaAs.- Electrical Properties.- The Problem of Chemical Inhomogeneities in Electronic Materials.- A Review of the Electrical Properties and Microstructure of Vanadium Phosphate Glasses.- Electrical Switching in Calcium Phosphate Glasses Containing Iron.- Role of Iron and Electrical Conductivity in Iron Calcium Phosphate Glasses.- Properties of Simultaneously Sputtered Thin Metal Films.- Indirect Exciton with Degenerate Valence Band in the Two-Photon Absorption in Semiconductors.- Structure of Chalcogenide Glasses.- Effect of Heat Treatment on Electrical Properties and Structure of As-Te-Ge Chalcogenide Thin Films.- Application of Avrami’s Equation to the Conductivity Changes of Amorphous Selenium.- Electrical Properties of Quenched Sn02 Films on Glass Substrates.- Physical Properties of Sputtered Amorphous Germanium Thin Films: The Role of Technological Parameters.- Magnetic Properties.- Some Recent Results on Paramagnetic Spin-Lattice Relaxation in Hydrated Paramagnetic Salts of the Iron Group.- ESR and Optical Studies of Induced Centres in Binary Silver and Alkali Borate Glasses.- ESR and Structural Studies on Pseudo-Alexandrite.- Magnetic and X-Ray Crystallographic Studies of a Series of Nitrosodisulphonates and Hydroxylamine-N, N-Disulphonates.- Radiation Effects.- Development of Materials for Energy-Related Applications.- Problem Areas in the First-Wall Materials of a Controlled Thermonuclear Reactor.- Simulation of 14-MeV Neutron Damage to Potential CTR Materials.- Deformation Luminescence of Irradiated CsI (Tl) Crystals.- A Bond-Type Criterion to Predict Bombardment-Induced Structure Changes in Non-Metallic Solids.- Chemistry.- Surface Area and Pore Structure of Low-Porosity Cement Pastes.- Adsorptive Behaviour of Alkali and Alkaline-Earth Cations onto Quartz.- Adsorption of Some Starches on Particles of Spar Minerals.- Sintering of Cobalt-Molybdenum Oxide Films on Alumina Supports.- Properties of Anodized Zinc in Alkaline Solutions.- of Volume 2.- of Volume 3.