Dielectric properties of B2O3-doped BiNbO4 ceramics

The densified B2O3-doped BiNbO4 ceramics were obtained after sintering at 960 °C. The dielectric properties of B2O3-doped BiNbO4 ceramics were studied. Samples sintered in air show low frequencies (from 1 to 100 kHz) dielectric relaxation behaviors at about 150 °C. The dielectric relaxation temperature would decrease when the sample was sintered in N2. The dielectric constant and loss at low frequencies increased rapidly and the microwave dielectric properties deteriorated with increasing B2O3 content when sintered in N2. The dielectric constant, Q-value and TCF-value of the 0.4 wt.% B2O3-doped BiNbO4 ceramic at 4.8 GHz are 41.5, 4400 and −2.4 ppm/°C, respectively. A defect model was proposed for the explanation of dielectric behavior of B2O3-doped BiNbO4 ceramics.