Enhanced electrocaloric effect in lead-free 0.9(K0.5Na0.5)NbO3-0.1Sr(Sc0.5Nb0.5)O-3 ferroelectric nanocrystalline ceramics

摘要

The environmentally friendly and low-cost ferroelectric refrigeration based on the electrocaloric effect (ECE) has attracted considerable attention to replace the conventional vapor compression cooling technology. The ECE has been experimentally demonstrated in lead-free 0.9(K0.5Na0.5) NbO3 -0.1Sr(Sc0.5Nb0.5)O-3 (KNN-0.1SSN) polycrystalline ferroelectric ceramics using an indirect thermodynamic method. A large electrocaloric effect ( adiabatic temperature change) of 0.28 K was observed near the transition temperature of 357 K for electric field 25 kV/cm, and that corresponds to an electrocaloric responsivity of Delta T/Delta E = 0.27 x 10(-7) KmV(-1), significantly larger than the pristine KNN based ceramics. A concurrent increment in specific entropy change of the material was also observed. The results indicate that ferroelectric KNN-0.1SSN materials possess a huge potential for electrocaloric refrigeration as a micro-cooler for electronic devices. (C) 2017 Elsevier B.V. All rights reserved.