Electrocaloric effects of sol-gel relaxor ferroelectric thin films

In this paper, the preparations of relaxor ferroelectric thin films, such as, (Pb,Ba)ZrO₃ (PBZ), (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMN-PT), (1-x)Pb(Mg_1/3Nb_2/3)O₃-xPbZrO₃ (PMN-PZ), Ba(Zr_xTi_1-x)O₃ (BZT), Pb(Sc_1/2Nb_1/2)O₃ (PSN), via chemical solution deposition have been reported. The synthesis of the corresponding sols of these thin films is sometimes very difficult in terms of lack of appropriate precursors, and low solubility of some precursors in alcohol and other organic solvents.  The sols are often unstable and irreproducible. In order to make the sol-gel processing of these materials reproducible it would be beneficial to identify the processes and reactions and to determine quantitatively the necessary amounts of the reagents.

Electrocaloric effects of these corresponding thin films are indirectly determined. The co-existence of ferroelectric and antiferroelectric phases that cause large entropy changes of the thin films under the applied field is responsible for large electrocaloric effect, particularly in the ferroelectric relaxers.