Novel high Curie temperature Ba2ZnSi2O7 ferroelectrics with low-permittivity microwave dielectric properties

Abstract Ba2ZnSi2O7 ceramics with a monoclinic structure (C 2/c) were prepared using the conventional solid-state method at 1200 °C for 3 h in air. The as-prepared ceramics show signs of weak ferroelectricity from the P-E loop and ferroelectric domains with 90° and 103° directions. Although an er anomaly appears at approximately 510 °C, the Curie temperature (Tc) of the Ba2ZnSi2O7 ceramics is 750 °C or higher. The ceramics also display low-permittivity microwave dielectric properties (er=8.09, Q×f=26,634 GHz, and τf=−51.46 ppm/°C). Therefore, the coexistence of high-Tc ferroelectricity and good microwave dielectric properties is beneficial to develop Ba2ZnSi2O7 ceramics into tunable-microwave and millimeter-wave devices such as capacitors, phase shifters, and oscillators.