Phase transitions and polarization switching in quasi-one-dimensional organic ferroelectrics of the phenyltetrazole family

Pseudospin models are proposed for the description of the phase transitions, dielectric characteristics, and polarization switching in two crystals of the phenyltetrazole family. One of them, APHTZ, is a canted ferroelectric, whereas the other, MPHTZ is a simple antiferroelectric. In APHTZ, the electric field, applied perpendicularly to the axis of spontaneous polarization, flips the polarization in one of the two sublattices, effectively rotating the nonzero net polarization by <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:msup> <a:mn>90</a:mn> <a:mo>∘</a:mo> </a:msup> </a:math> and switching the system between two different ferroelectric configurations. The temperature-electric field phase diagrams are constructed. The diagram topology appears to be typical for the Ising-like antiferroelectric systems.