Structural and Dielectric Characteristics in a Ca(Mg _1/3 Nb _2/3 )O ₃ –CaZrO ₃ System

Abstract

This study investigates the effect of CaZrO 3 (CZ) substitution on the evolution of an ordered structure in a Ca(Mg 1/3 Nb 2/3 )O 3 (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 ɛ 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 NbO 6 octahedral distortion is correlated with a decrease in relative permittivity and change of τ f toward more negative values. Simultaneously, the substitution of the Zr 4+ ion causes a linear increase in polarizability, and it also results in an increase in the relative permittivity.