Effects of ion polarizability and oxygen vacancy on microwave dielectric properties of fluorite‐structured Ce <sub>1−</sub> <i> <sub>x</sub> </i> Ca <i> <sub>x</sub> </i> O <sub>2−</sub> <i> <sub>x</sub> </i>
Yun Sun, Jiangtao Wu, Ying Tang, Huaicheng Xiang, Jie Li, Liang Fang
Abstract
Abstract X‐ray diffractometer with Rietveld refinement and Raman spectroscopy were used for phase analysis. Ca doping results in decreased ε r (24.09–21.52), Q × f (68 914–40 110 GHz), and τ f (−50.0 ppm/°C to −60.2 ppm/°C) all decrease, which obviously does not conform to the mutual constraint relationship among the three parameters of microwave dielectric properties. The ε r of Ce 1− x Ca x O 2− x ceramics is affected by the ion polarizability and the Ce rattling and valence states, among which the rattling of Ce cations plays a dominant role. The presence of oxygen vacancies in Ce 1− x Ca x O 2− x ceramics explains the decrease in Q × f . The τ ε , ε r , and α L are responsible for the decrease in τ f , especially for the τ αm ‐3 α L values.