Electric-field tunable electrocaloric effects from phase transition between antiferroelectric and ferroelectric phase

In this letter, orthorhombic Pb(Nb, Zr, Sn, Ti)O-3 (PNZST) and tetragonal (Pb, La)(Zr, Sn, Ti)O-3 (PLZST) antiferroelectric (AFE) thin films were deposited on LaNiO3/Pt(111)/TiO2/SiO2/Si(100) substrates via a sol-gel method. The electrocaloric effect (ECE) of PNZST and PLZST films originated from phase transition between AFE and ferroelectric were studied, based on their pyroelectric results. A large tunable ECE near room temperature was realized in these films under the function of electric field. As the applied electric field increased, the temperature corresponding to the peak of ECE was decreased for the orthorhombic PNZST films, while the temperature was increased for the tetragonal PLZST films. The maximum ECE of 0.040 K.cm/kV in PNZST films and 0.048 K.cm/kV in PLZST films was received at 323 and 305 K, respectively. The results indicated that AFE thin films had the potential for application in tunable cooling devices near room temperature. (C) 2014 AIP Publishing LLC.