Experimental Studies on Phase Transitions in Ferroelectric {N(CH₃)₄}₂ZnCl₄

Abstract

Thermal, dielectric and dilatational measurements were performed to study the phase transitions in ferroelectric {N(CH₃)₄}₂ZnCl₄. The temperature dependence of triple D-E hysteresis loop in ferroelectric Phase III (3.3∼6.0°C, C_2v⁹-P2₁cn) was observed in detail. The crystal is paraelectric along the b and c directions. A remarkable contraction of the lattice is seen in Phase V (−112∼−92°C, C_2h⁵-P12₁⁄c1). Calculated pressure-coefficients of transition temperatures were compared with the measured ones.