Tunable Microwave Properties of Barium Titanate‐Based Ferroelectric Glass‐Ceramics

BaTiO 3 ‐based ferroelectric glass‐ceramics with the composition 0.65(Ba 1− X Sr X )TiO 3 ·0.27SiO 2 ·0.08Al 2 O 3 ( X = 0.2–0.6) were fabricated, and their tunable dielectric properties were measured at microwave frequency. Major crystalline phases that precipitated during thermal treatment up to 1000°C were (Ba,Sr)TiO 3 , Ba 2 TiSi 2 O 8 , and BaAl 2 Si 2 O 8 . The Curie temperatures of the heated bulk samples were successfully tuned near room temperature at the composition between X = 0.2 and 0.3. A thick‐film sample with X = 0.3 showed 27% tunability at 5 GHz under 10 kV/cm bias voltage.