Dielectric Properties of Ferroelectric Rb2CdI4

Dielectric properties of ferroelectric Rb 2 CdI 4 were investigated. Since it is well known that the crystal surface reacts chemically with silver paste electrode and it makes dielectric quantities unstable, we reexamined dielectric properties using the sample with evaporated gold electrode. As the result, we obtained the stable results of the temperature dependence of the dielectric constant and pyroelectric charge. The experimental data established that ferroelectric Curie point of Rb 2 CdI 4 is 211 K and the spontaneous polarization P s is about 0.4 µC/cm 2 around 4 K. The frequency dispersion of the dielectric constant was also observed below the Curie point but its origin is still open.