Rochelle Salt as a Dielectric

TLDR

Rochelle salt slabs cut perpendicular to the a‑axis exhibit saturation and hysteresis in Braun tube oscillograms across temperatures. The dielectric constant of these slabs can reach 18,000, with temperature‑dependent saturation curves and mechanical deformation peculiarities, and half‑crystals up to 45 cm have been produced.

Abstract

Both saturation and hysteresis appear in Braun tube oscillograms made at various temperatures with a condenser whose dielectric consists of Rochelle salt slabs cut perpendicular to the a-axis. The dielectric constant for such slabs may reach a value of 18,000. Curves are also given, showing the variation in mechanical and electrical saturation with temperature. These correspond in only a general way to the piezoelectric constant's variation with temperature. Certain marked peculiarities are noted in the resulting mechanical deformation when Rochelle salt is excited with alternating potentials. Clear Rochelle salt half-crystals have been produced up to forty-five centimeters in length.