Structure and dielectric behavior of Pb(Mg1/3Nb2/3)O-3-Pb(Ni1/3Nb2/3)O-3-Pb(Zn1/3Nb2/3)O-3-PbTiO3 ferroelectric ceramics near the morphotropic phase boundary

摘要

Pb(Mg1/3Nb2/3)O-3-Pb(Ni1/3Nb2/3)O-3-Pb(Zn1/3Nb2/3)O-3-PbTiO3 (PMN-PNN-PZN-PT) ceramics with compositions of (1-x)-(0.14PZN-0.56PNN-0.30PT)-x(0.528PMN-0.132PNN-0.340PT) (x = 0.2,0.4,0.6,0.8) were prepared using the conventional mixed-oxide technique. X-ray diffraction results demonstrate that all the samples lie within the morphotropic phase boundary (MPB) region in the pure perovskite structure. The temperature dependence of the dielectric constant of the ceramics has been investigated in detail. All samples are characterized by a pronounced diffuse phase transition and weak frequency dispersion, and can no longer be regarded as typical relaxors. Excellent dielectric properties have been obtained for the selected compositions. The em value of the composition with x = 0.8 at 1 kHz reaches as high as 36,800, which implies that the quaternary compositions near the MPB merit further study. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.