Discovery of New Ferroelectrics: [H2dbco]2·[Cl3]·[CuCl3(H2O)2]·H2O (dbco = 1,4-Diaza-bicyclo[2.2.2]octane)

Abstract

Compound [H₂dbco]₂·[Cl₃]·[CuCl₃(H₂O)₂]·H₂O undergoes a sharp dielectric anomaly and a paraelectric-to-ferroelectric phase transition at approximately −23 °C with a spontaneous polarization of 1.04 μC cm⁻², being the first molecular metal coordination compound ferroelectrics with a large dielectric response involving a 2 orders of magnitude enhancement and distinct Curie phase transition point. This work has proved an effective way for exploration of new ferroelectrics based on a five-coordinated divalent metal through the combination of crystal engineering and Landau phase transition theory.