Lattice dynamics and terahertz response of microwave dielectrics: A case study of Al-doped Ca0.6Sm0.27TiO3 ceramics. Issue 12 (September 2022)

• Record Type: Journal Article
• Authors: Guo, Weijia; Ma, Zhiyu; Chen, Yugu; Lu, Yutian; Yue, Zhenxing
• Is Part Of: Journal of the European Ceramic Society. Volume 42:Issue 12(2022)
• Page Start: 4953
• Page End: 4961
• Publication Date: 2022-09
• Subjects: Microwave dielectric ceramics -- CaTiO3-based perovskite -- Lattice dynamics -- Terahertz specstropy -- Low dielectric loss; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2022.05.045
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Low-loss microwave dielectric ceramics are of great significance for fifth-generation telecommunication (5G) devices used for higher frequencies, while reducing the dielectric loss in the microwave band is still a technical challenge. Lattice dynamics and terahertz response are closely related to the polarization of dielectrics, and can be used as effective methods to explore the loss mechanism of microwave dielectrics. Here, Al 3+ was doped into the conventional high-permittivity ( ε r ) Ca1- x Sm2 x /3 TiO3 ( x = 0.4) ceramic system, enhancing the Q × f values significantly. Raman spectra, thermally stimulated depolarization currents (TSDC) and terahertz time-domain spectra (THz-TDS) together showed that the stiffness of cation vibration became stronger when z value was larger, indicating a smaller damping of the lattice vibration, and leading to lower extrinsic losses and higher Q × f values. The relationship between lattice dynamics, defect behavior and microwave dielectric loss will provide a significant reference for the development of low-loss microwave dielectric ceramics. Highlights: Medium/high- ε r dielectrics of microwave/terahertz devices are developed. The Q × f values in the microwave and terahertz bands are essentially constant. Bond strength, defects, lattice vibration and dielectric loss have strong correlation.