Accession Number : AD0605663

Title :   MIXED BISMUTH OXIDE (MBO) TYPE FERRIELECTRICS,

Corporate Author : CATHOLIC UNIV OF AMERICA WASHINGTON D C

Personal Author(s) : Pulvari,Charles F.

Report Date : MAY 1964

Pagination or Media Count : 64

Abstract : As a result of accumulated information, a new family of ferrielectric materials was discovered and the simplest mixed bismuth oxide with a layer-type structure, having the formula Bi4Ti3O12 was found to be a degenerate antiferroelectric material exhibiting a pronounced and stable threshold switching field. This fact establishes the second group of ferrielectrics in the mixed bismuth oxides with a layer-type structure. It is suggested that this new group of ferrielectrics be called 'MBO Type Ferrielectrics.' It was also revealed that this new material exhibits a stable ferrielectric state from nearly 0K up to several hundred degrees centigrade and represents, at present, a material with the widest region of stable ferroelectric behavior. The preparation of these complex crystals, as well as their morphology, is discussed. The result of electrical and optical measurements are presented and the domain structure of the crystals has been determined. Some of the semiconductive properties were studied and the effect of impurities on the threshold and bias fields is presented. A foundation for a theoretical explanation of a number of new phenomena found in ferrielectrics has been laid. (Author)

Descriptors :   (*FERROELECTRIC MATERIALS, BARIUM COMPOUNDS), (*BARIUM COMPOUNDS, OXIDES), ANTIFERROELECTRICITY, TITANATES, CRYSTAL STRUCTURE, DIPOLE MOMENTS, HEAT TREATMENT, ELECTRICAL PROPERTIES, IMPURITIES

Distribution Statement : APPROVED FOR PUBLIC RELEASE