Structural and Dielectric Characteristics in a Ca(Mg1/3Nb2/3)O3–CaZrO3 System

This study investigates the effect of CaZrO₃ (CZ) substitution on the evolution of an ordered structure in a Ca(Mg_1/3Nb_2/3)O₃ (CMN) system using Raman spectroscopy, X-ray diffractometry, and transmission electron microscopy. It indicates that a (1? x ) CMN?( x )CZ solid solution has the 1:2 and 1:1 ordered structure distorted by the antiphase, the inphase tilting of oxygen octahedra, and the antiparallel shift of A-site cation. A distinct correlation is noted between the transition of the ordered structure and microwave dielectric properties. The differences in ?_r and τ_f are attributed exclusively to the differences in the type of cation arrangement. The structure with the 1:2 ordering exhibits a lower relative permittivity and a more negative τ_f than the structure with the 1:1 ordering. The increased fraction of compressed Nb–O bond in the 1:2 ordered structure associated with a large NbO₆ octahedral distortion is correlated with a decrease in relative permittivity and change of τ_f toward more negative values. Simultaneously, the substitution of the Zr⁴⁺ ion causes a linear increase in polarizability, and it also results in an increase in the relative permittivity.