Lattice parameter fluctuations of relaxor ferroelectrics determined by X‐ray diffraction method

Abstract

AbstractRelaxor ferroelectrics possess prominent dielectric and piezoelectric properties thus have been utilized in many advanced electromechanical devices. However, the atomic‐scale mechanism of their excellent electromechanical properties remains vague, which hinders the development of high‐performance ferroelectrics. In this work, we investigated the lattice parameter fluctuations for Pb(Mg1/3Nb2/3)O3–PbTiO3 relaxor ferroelectric ceramics, with a comparison of non‐relaxor ferroelectric ceramics, including BaTiO3, SrTiO3, and Pb(Zr,Ti)O3, at their respective paraelectric phase by X‐ray diffraction. We found that the fluctuations of lattice parameter were much larger in relaxor ferroelectrics than that in conventional ferroelectrics in the paraelectric phase, revealing a significant distinction between relaxor ferroelectrics and conventional ferroelectrics from the respect of atomic arrangement. Transmission electron microscopy experiments and X‐ray scattering‐intensity simulations indicated that the large fluctuations of lattice parameter in relaxor ferroelectrics can be attributed to the ordered–disordered arrangement of B‐site cations at the nanoscale. This work offers a new method to study the chemical arrangement difference between relaxor ferroelectrics and conventional ferroelectrics and may help us to explore the atomic‐scale origin of ultrahigh piezoelectric properties in relaxor ferroelectrics.