Correlation of Phase Structure, Defect Relaxation, and Microwave Dielectric Properties in Low-Loss Mgn+1TinO3n+1 Ceramic Systems

作者：Shuai Ma, Xiaohua Zhang, Xiaohua Zhang, Jie Zhang, Xiaohui Zhang, Xiaohui Zhang, Yu Liu, Chenglong Yu, Zhenxing Yue · 发表于：ACS Applied Materials & Interfaces · 年份：2025 · DOI：10.1021/acsami.4c16580 · 被引用次数：6 · 研究领域：Microwave Dielectric Ceramics Synthesis、Ferroelectric and Piezoelectric Materials、Multiferroics and related materials

Low-loss microwave dielectrics are of significant importance for the miniaturization and integration of microwave devices. In this paper, the ceramics of nominal composition Mg n +1 Ti n O 3 n +1 ( n = 3–6) are synthesized, and the correlations among their phase compositions, defect behaviors, and microwave dielectric properties are systematically investigated. The analyses indicate that the Mg n +1 Ti n O 3 n +1 ceramics are a biphasic system consisting of hexagonal ilmenite-structured MgTiO 3 and cubic spinel-structured Mg 2 TiO 4 . The Rietveld refinement results demonstrate that as the n value increases, the content of the MgTiO 3 phase gradually increases, while that of the Mg 2 TiO 4 phase decreases. The results of the thermally stimulated depolarization current (TSDC) indicate that the oxygen vacancy-related defects are considered to be the main types of defects in Mg n +1 Ti n O 3 n +1 . As the value of n increases, the increase of the MgTiO 3 phases with a more stable crystal structure leads to a gradual decrease in the concentration of oxygen vacancies. The Mg n +1 Ti n O 3 n +1 ceramics exhibit excellent microwave dielectric properties at n = 6: ε r = 17.55, Q × f = 284,600 GHz, and τ f = −46.39 ppm/°C. In addition, the relationship between the dielectric constant and the electric field distribution is solved utilizing high-frequency structure simulator (HFSS) software, and the Q × f values are also predicted. The low-frequency dielectric temperature spectra and di...