Tuning the order-disorder of Zn2-2xLixGa4+xO8 spinel towards high-performance microwave dielectric ceramic

作者：Tang, Ying; Du, Qianbiao; Xiang, Huaicheng^*; Fang, Liang^*

来源：Journal of Alloys and Compounds, 2022, 927: 167026.

DOI：10.1016/j.jallcom.2022.167026

• Zn2-2xLixGa4+xO8 ceramics
• Microwave dielectric properties
• Structure regulation
• P-V-L theory

High-Q Zn2-2xLixGa4+xO8 (0 <= x <= 1) ceramics with spinel structure were synthesized using the traditional solid-state method. Li+ and Ga3+ are introduced into ZnGa2O4 ceramic to tune the order-disorder of the structure. A disordered face-centered cubic phase is achieved in the compositional range of x < 0.9, and an ordered primitive cubic spinel is found as x >= 0.9. As x increases, Li+ preferentially occupies the octahedral site, causing partial Ga3+ to occupy the tetrahedron, making a 1:3 (Li: Ga) ordered structure in the octa-hedral site. A low relative permittivity (er) of 10.1 and a relatively stable temperature coefficient of re-sonance frequency (tau(f)) of - 52.3 ppm/degrees C of Li0.9Zn0.2Ga4.9O8 ceramic (x = 0.9) were attained when sintered at 1300 degrees C. A maximum quality factor was achieved at x = 0.75 (Li0.75Zn0.5Ga4.75O8) with Qxf = 120,370 GHz (f = 13 GHz). Moreover, the intrinsic influence mechanism of crystal structure on the dielectric properties was explored through the P-V-L chemical bond theory.

• 单位
  桂林理工大学