Dielectric Properties of Single Crystals of Barium Titanate

The dielectric properties of some of the single crystals of barium titanate prepared by H. F. Kay and R. G. Rhodes (see preceding communication) have been measured at various field strengths and temperatures. The average linear dimension of the crystals available was 0.4 mm., and it was found convenient to mount them in thin disks of a phenolformaldehyde resin. Silver electrodes were vaporized on to the two exposed faces, and the electrical contacts were pressed against the silver on the resin, so as not to stress the crystal. The electric field was applied along a direction which was a cubic axis above the Curie point, and contained a mixture of the three tetragonal axes, in various domains, at room temperature. A circuit essentially similar to that of Sawyer and Tower1 was used to display the polarization-electric field curve at 50 cycles per second on a cathode ray tube.