Ultralow-loss Sr1+xMgGe2O6+x ceramics: Sintering behavior, microstructure, covalence, lattice vibration, and dielectric properties

作者：He, Yinghan; Wei, Xiaoli; Chen, Xiuli; Zhou, Huanfu^*

来源：Ceramics International, 2023, 49(22): 36536-36544.

DOI：10.1016/j.ceramint.2023.08.337

• Low permittivity
• Lattice vibration
• Bond energy
• Covalence
• Microwave dielectric properties

Sr1+xMgGe2O6+x ceramics were prepared by the solid-state reaction method (SSR). The effects of Sr2+ nonstoichiometry on phase composition, sintering characteristics, microstructure, and microwave properties were analyzed. XRD detected a slight excess of strontium to produce the secondary phase Sr2MgGe2O7. Rietveld refinement obtained the structural parameters, and the crystal structure was studied. SEM revealed that excessive strontium promoted grains' growth and increased ceramics' density. Raman spectrum indicates that the FWHM is closely related to microwave properties. The change of Q x f was explained by analyzing the packing fraction and average covalence. The distortion of the GeO4 tetrahedron and bond energy revealed the relationship between zf and crystal structure. Sr1.03MgGe2O6.03 ceramics sintered at 1250 degrees C have the best microwave properties of er = 8.69, Q x f = 77660 GHz, zf = -74 ppm/degrees C.

• 单位
  桂林理工大学