A Displacive-Type Metal Crown Ether Ferroelectric Compound: Ca(NO3)2(15-crown-5)

摘要

Following the Curie symmetry principle and Aizu rule, we discovered there is a centrosymmetric-to-noncentro-symmetric phase transition in Ca(NO3)2(15-crown-5) at T_c = 205 K. The transition was confirmed by differential scanning calorimetry and second harmonic generation measurements. The transition gives rise to excellent ferroelectricity, such as a giant dielectric anomaly, with faster polarization switching (5 × 10~(-5) s) of up to 107 times without showing fatigue. The ferroelectric mechanism is attributable to the coordination environmental distortion of the central Ca atom. This finding can throw light on the further research in metal-organic ferroelectrics.