Phase Structure, Bond Features, and Microwave Dielectric Characteristics of Ruddlesden-Popper Type Sr 2 TiO 4 Ceramics

• Published in: Materials Vol. 16; no. 14
• Main Authors: Yang, Jun, Pang, Jinbiao, Luo, Xiaofang, Ao, Laiyuan, Xie, Qiang, Wang, Xing, Yang, Hongyu, Tang, Xianzhong
• Format: Journal Article
• Language: English
• Published: Switzerland 24.07.2023
• Subjects: P–V–L complex chemical bond theory; microwave dielectric properties; Sr2TiO4
• ISSN: 1996-1944; 1996-1944

This work studied the phase constitution, bond characteristics, and microwave dielectric performances of Sr TiO ceramics. Based on XRD and Rietveld refinement analysis, pure tetragonal Ruddlesden-Popper type Sr TiO ceramic is synthesized at 1425~1525 °C. Meanwhile, the microstructure is dense and without porosity, indicating its high sinterability and densification. Great microwave dielectric performances can be obtained, namely an value of 39.41, and a value of 93,120 GHz, when sintered at 1475 °C. Under ideal sintering conditions, the extrinsic factors are minimized and can be ignored. Thus, the intrinsic factors are considered crucial in determining microwave dielectric performances. Based on the P-V-L complex chemical bond theory calculation, the largest bond ionicity, and proportions to the bond susceptibility from Sr-O bonds suggest that Sr-O bonds mainly determine the dielectric polarizability. However, the Ti-O bonds show lattice energy about three times larger than Sr-O bonds, emphasizing that the structural stability of Sr TiO ceramics is dominated by Ti-O bonds, and the Ti-O bonds are vital in determining the intrinsic dielectric loss. The thermal expansion coefficient value of the Sr TiO structure is also mainly decided by Ti-O bonds.