Hysteresis and tunability characteristics of Ba(Zr,Ti)O3 ceramics described by First Order Reversal Curves diagrams

The First Order Reversal Curves (FORC) diagrams method is proposed for the characterization of the switching process and ac-tunability in BaZr0.10Ti0.90O3 ceramics prepared via solid state reaction. The properties induced by different microstructures, having two extreme grain sizes of 0.75 and 3.3 mu m are investigated by monitoring the changes of the FORC diagrams. The maximurn of FORC distribution is located at low fields independently on the grain size and no clear separation between the reversible/irreversible contributions to the polarization are found. A higher degree of the local inhomogeneity is characteristic to the fine ceramic. The FORC susceptibility related to the ac-tunability determined on the major hysteresis loop is very sensitive to the grain size: it is much smaller in the fine material, due to the pinning of the domain walls by different types of defective areas. (C) 2007 Elsevier Ltd. All rights reserved.