Effects of Ionic Coordination Bonding on Microwave Dielectric Properties of Y2CaBGa4O12 (B = Zr, Sn) Garnets Effects of Ionic Coordination Bonding on Microwave Dielectric Properties of Y2CaBGa4O12 (B = Zr, Sn) Garnets AITranslate

Basic Information:

DOI：https://doi.org/10.1021/acsaelm.2c00486

Chinese Library Classification Number:

Citation Information:

Two garnet-type electronic functional ceramics, Y2CaBGa4O12 (B = Zr, Sn), are reported, including their preparation process, microwave dielectric properties, and bonding properties. Acceptable microwave dielectric properties of εr = 12.1 ± 0.1, Q × f = 85,900 ± 2000 GHz, and τf = −45.5 ± 1.5 ppm/°C for Y2CaZrGa4O12 and εr = 10.6 ± 0.1, Q × f = 95,750 ± 2000 GHz, and τf = −53.1 ± 1.8 ppm/°C for Y2CaSnGa4O12 were achieved at 1450 °C. Compared with the ideal bond lengths, Ca–O, Zr–O, and Sn–O bonds are compressed, whereas the Y–O, Ga(1)–O, and Ga(2)–O bonds are in an expanded state. The positive weighted average difference factors (⟨d⟩) indicate that the ions of Y2CaZrGa4O12 (0.023 v.u.) and Y2CaSnGa4O12 (0.015 v.u.) are in an underbonded state on average, and the overall structures are in a slightly expanded state. The ionicity and energy of the bonds in Y2CaBGa4O12 ceramics were analyzed by the dielectric theory of chemical bonds. Compared to Y2CaSnGa4O12, the larger εr in Y2CaZrGa4O12 comes down to the combined effect of the larger ionic polarizability of Zr4+ and a more substantial rattling effect, which also causes its τf to move toward the near-zero direction.