Enhanced ferroism in mechanically processed and environmentally friendly Ba0.30Na0.70Ti0.30Nb0.70O3 ceramics

Environmentally friendly Ba0.30Na0.70Ti0.30Nb0.70O3 ceramics were processed by high-energy ball milling and oxidizing heat treatments. Their pyroelectric, dielectric and ferroelectric properties were significantly improved by means of preventing residual phases through the synthesis protocol. These samples showed considerable improvements in the dielectric constant and pyroelectric coefficient, which reached 6000 (at 1 kHz) and 170 nC cm(-2) K-1 at 300 K, respectively. The potential for the application of Ba0.30Na0.70Ti0.30Nb0.70O3 as an electrocaloric material was demonstrated by isothermal entropy change (Delta S-T= 0.026 J kg(-1) K-1) measurements. (C)2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.