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

TL;DR

This study investigates how the dielectric properties and structural order in complex relaxor ceramics vary with composition, revealing that larger ordered domains do not necessarily correlate with relaxor behavior, contrary to traditional understanding.

Contribution

It provides new insights into the relationship between dielectric properties and nano-scale structural order in relaxor ceramics, challenging existing theories.

Findings

Higher PIN content decreases permittivity maxima and Tmax.

All compositions exhibit slim ferroelectric hysteresis loops.

Ordered domains are nano-sized and separated by antiphase boundaries.

Abstract

The dielectric and structural order-disorder properties of as-sintered complex perovskite (x)Pb(In1/2Nb1/2)O3:(1-x)Pb(Mg1/3Nb2/3)O3 ceramics are highly influenced by the quantity of Pb(In1/2Nb1/2)O3 (PIN). High PIN quantity causes the relative permittivity maxima to decrease and the temperature (Tmax) to increase. Also, strong frequency dispersion is dominant in the relative permittivity plotted against the temperature. In the ferroelectric hysteresis loop measurements, the maximum values of electric displacements (Dmax) decrease with increasing PIN. The ceramics in the composition range x = 0.1 to 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.