Crystal structure and microwave dielectric properties of a novel rock-salt type Li3MgNbO5 ceramic

Ceramic compositions for 5G devices containing niobium: A survey

“…The phase purity of Li 3 MgNbO 5 was validated by X-ray diffraction in specimens sintered in the 1200−1280 • C. The grain size increased from ∼11 to ∼40 μm according to the sintering temperature. Optimal properties (ε r = 16.2, Qxf = 96 796 GHz, and τ f = −24.8 ppm/ • C) were obtained for sintering at 1260 • C. 45 Adjustment of the temperature coefficient of resonant frequency was accomplished in the composite 0.96Li 3 MgNbO 5 -0.04CaTiO 3 sintered at 1250 • C with ε r = 19.12, Qxf = 70 814 GHz (at 6.105 GHz), and τ f = 2.6 ppm/ • C. 45 Li 3 (Mg 1−x Zn x ) 4 NbO 8 Li 3 Mg 4 NbO 8 with partial substitution of Zn 2+ in the Mg 2+ site was intended to reduce the dielectric loss and contribute to the temperature stability. Specimens with x = 0.02, 0.04, 0.06, and 0.08 in the Li 3 (Mg 1-x Zn x ) 4 NbO 8 were sintered in the 1050−1150 • C range utilizing the stackfiring method (similar to the use of the powder bed procedure) to avoid Li loss.…”

“…The grain size increased from ∼11 to ∼40 μm according to the sintering temperature. Optimal properties (ε r = 16.2, Qxf = 96 796 GHz, and τ f = −24.8 ppm/°C) were obtained for sintering at 1260°C 45 . Adjustment of the temperature coefficient of resonant frequency was accomplished in the composite 0.96Li 3 MgNbO 5 ‐0.04CaTiO 3 sintered at 1250°C with ε r = 19.12, Qxf = 70 814 GHz (at 6.105 GHz), and τ f = 2.6 ppm/°C 45 …”

“…Pellets obtained with an addition of 0.5 wt.% MBS glass were sintered at 925 • C/4 h achieving 95% of relative density. The microwave dielectric properties were ε r = 14.5, Qxf = 80 759 GHz, and τ f = −20.7 ppm/ • C. 39 LBSCA adding: Li 3 Mg 2 NbO 6Ceramics with an addition of LBSCA glass were prepared with 52 45. Li 2 O:31.06 B 2 O 3 :11.99 SiO 2 :2.25 CaO:2.25 Al 2 O 3 at 1000 LBSCA) for a sintering dwell temperature of 950 • C. No secondary phases were detected by X-ray diffraction after sintering at 925 • C. Increase of the sintering temperature to 975 • C resulted in abnormal grain growth in specimens containing 0.5 wt.% of LBSCA.…”

Temperature-stable Li4Ti3O8 composite microwave dielectric ceramics and their applications in dielectric resonator antennas

“…The rock salt structure ceramics typically exhibit excellent microwave dielectric properties, such as Li 3 NbO 4 , Li 3 Mg 2 NbO 6 , Li 3 Mg 4 NbO 8 , Li 3 MgNbO 5 , and Li 2 Mg 3 SnO 6 . 12–16 The Li 2 TiO 3 ceramics ( ε r = 22.1, Q × f = 63 525 GHz, and τ f = +20.3 ppm °C −1 ), also demonstrating rock salt structures, have garnered significant attention due to their straightforward preparation process, abundant raw materials, and commendable performances. 17 However, Li 2 TiO 3 ceramics have certain drawbacks, including the requirement for a high sintering temperature of 1300 °C and a relatively high τ f value of +20.3 ppm °C −1 .…”