Ferroelectricity in Glycine Silver Nitrate

Glycine silver nitrate, NH₂CH₂COOH·{}AgNO₃, is ferroelectric below -55^∘{}C. At -195^∘{}C the spontaneous polarization is 0.55×{}10^-6 coulomb/cm², and the coercive field is 740 v/cm. The transition appears to be of second order. A differential thermal analysis does not reveal a specific heat anomaly. No dielectric anomalies appear between 4^∘{}K and -55^∘{}C. The spontaneous polarization here, as in triglycine sulfate and isomorphs, is attributed to disturbance of the planarity of the glycine ion by the crystalline field.