Dielectric properties of bismuth zinc niobate ceramics

Abstract

The structure and dielectric properties of Y3+ substitution in the A site of Bi1.5-xZnNb1.5O7 ceramic were investigated by X-ray diffraction, scanning electron microscopy and precision impedance tester. The results show that the structure of the ceramics remains a pyrochlores phase with Y3+ substitution of x ≤ 0.2 and exhibits a second phase with the Y3+ substitution of x ≥ 0.4. With the increase of the Y3+ substitution, the bulk density, grain size and dielectric constant decrease while the temperature for densification and dielectric loss increase. With the Y3+ substitution (x ≤ 0.8), the temperature coefficient of the dielectric constant is optimized and the samples have excellent stability as a function of frequency. The relaxation behavior in the low temperature range exhibits a regular change with Y3+ substitution. The dielectric constant decreases and the dielectric constant peak flattens with the increase of Y3+ substitution.