Detection of Alpha Sub-Phase Between Para- and Ferroelectric Phase of a Fluorinated Compound

Abstract

Measurements of spontaneous polarization and tilt angle vs. temperature were performed for a fluorinated ferroelectric compound displaying large spontaneous polarization and tilt angle as well. Transition between the paraelectric and alpha sub-phase was identified as a second order type whereas the alpha sub-phase—ferroelectric phase transition seems to show a tri-critical point behavior. Spontaneous polarization measurements as well as texture observation on a mono-domain thin layer of the sample being under strong electric filed confirm the existence of the sub-phase alpha between para- and ferroelectric phase. It is demonstrated for the first time that in the narrow temperature range of the alpha sub-phase there is a pronounced distortion on the curve presenting temperature dependence of spontaneous polarization.