BaZnSi3 O8 ceramic was prepared by the conventional solid-state method and sintered at 1100 °C. XRD and synchrotron Rietveld refinement analyses revealed the BaZnSi3 O8 ceramic presented a monoclinic structure with a space group of P21 /a (No.14), which is reported for the first time. The BaZnSi3 O8 ceramic presented a weak ferroelectricity, which was confirmed by the P-E loop and the 90° nanoscale ferroelectric domain. Although ϵr -T displayed two ϵr abnormal peaks at 400 °C and 460 °C, the Curie temperature (Tc ) was located at 460 °C according to the dielectric loss and Curie-Weiss law. Moreover, the BaZnSi3 O8 ceramic exhibited optimized microwave dielectric properties with ϵr =6.55, Q×f=52400 GHz, and τf =-24.5 ppm/°C. Hence, the BaZnSi3 O8 ceramic in the ternary BaO-ZnO-SiO2 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.
Keywords: crystal structure; electroceramics; ferroelectricity; silicate.
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