Thermal Response at the Dipolar-Glass to Ferroelectric Transition in Structuraly Disordered Ferroelectric Materials

Abstract

Presented in this paper of this special issue of Ferroelectrics, dedicated to Prof. Wolfgang Kleemann, is our recent study of thermal response near the dipolar glass to ferroelectric (G-F) transition studied by a high resolution calorimetry in relaxor ferroelectric 9/65/35 PLZT ceramics. By theoretical investigations based on spherical random bond random field (SRBRF) model it is predicted that the discontinuous electrocaloric change (EC) of temperature should be observed at the G-F transition line in an electric field–temperature (E-T) phase diagram. Experimental results confirm existence of such discontinuous EC jump in temperature in the canonical relaxor system 9/65/35 PLZT ceramics, thus confirming the existence of the first order G-F transition line in the E-T phase diagram of the perovskite relaxor ferroelectrics.

Keywords:

• Relaxor ferroelectric
• electrocaloric
• glass
• phase transition

Acknowledgments

This work was supported by the NAMASTE Centre of Excellence and Slovenian Research Agency under the program P1-0125 and the project J1-2015.