Ba2BiSbO6: A novel microwave dielectric ceramic with monoclinic structure

Abstract

A novel Ba2BiSbO6 microwave dielectric ceramic was prepared via the traditional solid-state method, and the microwave dielectric properties of Ba2BiSbO6 were investigated for the first time. The analysis of X-ray diffraction patterns indicated that the pure monoclinic Ba2BiSbO6 phase could be formed in the temperature range of 950–1150 °C. Rietveld refinement results further confirmed that Ba2BiSbO6 belonged to a monoclinic system with space group I2/m (12). Dense and homogeneous microstructures of Ba2BiSbO6 ceramics sintered at 1100–1150 °C could be revealed from the scanning electric microscope. The bond ionicity, lattice energy and coefficient of the thermal expansion were initially calculated based on the complex chemical bond theory. The complex dielectric constant and loss were gained from the fitting data of far infrared spectra, which were in good agreement with the measured values. The optimum microwave dielectric properties of εr = 26.61, Q·f = 13,764 GHz (at 5.95 GHz) and τf = −26.6 ppm/°C were achieved in Ba2BiSbO6 ceramic sintered at 1100 °C.