Physicochemical aspects of the development of MW dielectrics and their use

Various methods for developing MW dielectrics based on multiphase and monophase systems have been considered. It has been shown that multiphase MW dielectrics can be developed in several ways: (a) by using paraelectrics together with antiferroelectrics in gradient MW dielectrics, (b) by using volume temperature compensation; (c) by developing composite materials containing an organic matrix and a fine inorganic multiphase filter. Monophase MW dielectrics can be developed on the basis of solid solutions, in which: (a) positive temperature dependence of permittivity (tau (epsilon)) in compounds forming solid solution is attained by the existence of phase transitions or by the presence of a mobile sublattice; (b) aliovalent substitution in cation sublattices affects the phonon spectrum, resulting in a high temperature stability of electrophysical properties. Examples of the use of MW dielectrics developed in engineering are given. (C) 2001 Elsevier Science Ltd. All rights reserved.