ULTRA-FINE PARTICLE SIZE FERROELECTRICS.
Quarterly progress rept. no. 5, 16 Apr15 July 63,
CHICAGO UNIV IL HUMAN DYNAMICS LAB
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Studies were directed to the preparation and evaluation of dense, unsupported films of controlled-purity barium titanate with sub-micron crystallite sizes. As a result, it has been possible to obtain films 30 to 60 microns thick, in pieces as large as one inch square, substantially free from pinholes. Although no direct measurement of density was performed, examination of the films with the aid of both the optical and electron microscope, and a consideration of their electrical properties, suggested a high degree of densification. Films thus prepared from high purity BaTiO3 incorporating, for example, 2.5 Ta2O5 and 0.5 SiO2, possessed grain sizes averaging 0.3 microns the dielectric constant was about 3000 at room temperature, and the temperature variation was similar to the behavior of thick specimens of a similar composition and grain size. Breakdown field was about 55 kVcm. Author