Crystal Structure and Ferroelectric Evidence of BaZnSi<sub>3</sub>O<sub>8</sub>, a Low‐Permittivity Microwave Dielectric Ceramic
Zheng‐Yu Zou, Xiaoqiang Song, Lei Jiang, Changlai Yuan, Wenzhong Lü, Yongming Hu, Wen Lei
Abstract
Abstract BaZnSi 3 O 8 ceramic was prepared by the conventional solid‐state method and sintered at 1100 °C. XRD and synchrotron Rietveld refinement analyses revealed the BaZnSi 3 O 8 ceramic presented a monoclinic structure with a space group of P 2 1 / a (No.14), which is reported for the first time. The BaZnSi 3 O 8 ceramic presented a weak ferroelectricity, which was confirmed by the P – E loop and the 90° nanoscale ferroelectric domain. Although ϵ r – T displayed two ϵ r abnormal peaks at 400 °C and 460 °C, the Curie temperature ( T c ) was located at 460 °C according to the dielectric loss and Curie–Weiss law. Moreover, the BaZnSi 3 O 8 ceramic exhibited optimized microwave dielectric properties with ϵ r =6.55, Q × f =52400 GHz, and τ f =−24.5 ppm/°C. Hence, the BaZnSi 3 O 8 ceramic in the ternary BaO‐ZnO‐SiO 2 system possessed both weak ferroelectricity and microwave dielectric properties. These results are expected to break the technical barrier of ferroelectric phase shifter applications in microwave and even millimeter‐wave frequency bands.