Relationship between dielectric properties and structural long-range order in (x)Pb(In1/2Nb1/2)O3:(1-x)Pb(Mg1/3Nb2/3)O3 relaxor ceramics

The dielectric and structural order-disorder properties of as-sintered complex perovskite (x)Pb(In1/2Nb1/2)O-3:(1-x)Pb(Mg1/3Nb2/3)O-3 ceramics are highly influenced by the quantity of Pb(In1/2Nb1/2)O-3 (PIN). A high PIN quantity causes the relative permittivity maxima (epsilon(max)) to decrease and the temperature (T-max) to increase. Also, strong frequency dispersion is dominant in the relative permittivity when plotted against the temperature. In ferroelectric hysteresis loop measurements, the maximum values of electric displacements (D-max) decrease with increasing PIN. The ceramics in the composition range x = 0.1-0.8 behave as ferroelectric relaxors and exhibit very slim hysteresis loops for all these compositions. Transmission electron microscopy (TEM) studies show that the size of the 1:1 structural ordered domains is influenced by the PIN quantity. The relationship between the dielectric properties and the long-range 1:1 order in these relaxors appear to be in conflict with the commonly accepted order-disorder behavior in complex perovskite ferroelectrics, in which large structural domains correspond with the tendency to depart from the relaxor state. TEM observations show that individual 1:1 ordered domains in (x)PIN:(1 - x)PMN ceramics are composed of numerous nano-sized ordered domains, separated by fine antiphase boundaries. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.