Ferroelectric performances and crystal structures of (Pb, La)(Zr, Ti, Nb)O3

In this study, we focused on Nb and La substituted Pb(Zr, Ti)O-3: i.e., (Pb, La)(Zr, Ti, Nb)O-3. As for the samples, dependences of ferroelectric properties on La and Nb compositions were examined. In addition, the crystal structures were analyzed by the Rietveld method, and then a relationship between the metal compositions and the crystal structures were discussed. From P-E hysteresis loop measurements, it was found that the remanant polarization of Pb(Zr, Ti)O-3 was increased by both the La and Nb substitutions although the heavy substitution of La had an undesirable effect. It was also indicated that the Curie temperature decreased with increasing La content. The Rietveld analysis using synchrotron X-ray diffraction patterns demonstrated that the structure distortion was relaxed by the La and Nb substitutions. Such a change in the crystals was well consistent with the harmful effects on the Curie temperature and the remanent polarization by the heavy La substitution. (C) 2013 Elsevier Inc. All rights reserved.