Dielectric observation of a probably antiferroelectric high pressure phase in the ferroelectric Tris-Sarcosine Calcium Chloride (TSCC)

Dielectric susceptibility and ferroelectric hysteresis measurements on TSCC show that the 2nd-order paraelectric-ferroelectric (PE-FE) phase boundary beginning at (130.8 K, 1 bar) runs with pronounced curvature to (176.8 K, 5.03 kbar), where a new phase of low dielectric susceptibility appears. This phase is hypothesized to be antiferroelectric (AFE) with 3 possible structures: orthorhombic (P2₁2₁2₁, piezoelectric) or monoclinic ($\text{P2}{}_1\text{a}$ or $\text{P2}{}_1\text{n}$, centrosymmetric). The FE-AFE phase boundary was determined down to (81.0 K, 2.60 kbar) and the PE-AFE boundary up to (225.5 K, 6.82 kbar). Both the FE-AFE and PE-AFE transitions are of 1st order over the range studied.