Dielectric oxyfluorides with high relative permittivity - at and below ambient temp., and insensitive to changes in frequency

摘要

Dielectric oxyfluorides prodn. by heating a mixt. of simple oxides at adequate time and temp. in a dry inert atmos. the mixt. being the precursor of a ferroelectric reference oxide and contg. a metal fluoride, so that a definite cpd. is obtd. in powder form, the amt. of fluoride and oxides being chosen so that the total cations equal the total anion in the cpd. obtd. The cpd. obtd. may be sintered or pulverised in vacuum and the mixt. may contain a rare earth oxide, e.g. of Gd, or a oxide such a TiO2. The ferroelectric reference oxide may be a simple or complex perovskite; a pyrochlore; of type LiNbO3 or YMnO3; a tungstate bronze e.g. AB2O6 or ABCD5O15; or layer structures e.g. A2BO6. Used for electronic devices operating below ambient temp, also TV receivers. Provides high relative permittivity which is not sensitive to changes in temp. or the frequency of the applied A.C. Field.