Dilatometric Study of Ferroelectric Rb2CdI4 Monoclinic Crystal Grown by Czochralski Method

Crystal growth of Rb2CdI4 was performed by Czochralski method. Transparent colourless crystals with monoclinic structure were obtained. Temperature dependence of the dielectric constant along the b-axis was measured with variation of frequency. The thermal expansions xi (i = a, b, c and a′; a ′ = a + c) along the four independent axes were measured both by clip-type strain-gauge dilatometer and X-ray diffraction methods. These results show distinct anomalies associated with the ferroelectric transition at TC = 210 K.