Microwave dielectric properties of Ba[(Zn 1− xCo x) 1/3Nb 2/3]O 3 ceramics

Abstract

Microwave dielectric ceramics of Ba[(Zn 1− x Co x ) 1/3Nb 2/3]O 3 ( x=0–0.8) were prepared by solid-state reaction method. The microwave dielectric properties, such as dielectric constants, Q× f values and τ f (temperature coefficient of resonant frequency) were studied as a function of compositions and sintering temperatures. The results revealed that the dielectric constant and Q× f value decrease almost linearly with increasing x. With x increasing from 0 to 0.8, the dielectric constant decreases from 42 to 33, and Q× f value from 75,491 to 20,248 GHz. A nearly zero τ f ceramic with dielectric constant of 33 and Q× f value of 20,248 GHz was obtained at x=0.8. The sintering temperature has slight effect on dielectric constant, but significant on Q× f value. The microstructures and crystal structures were characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis techniques to reveal the mechanisms.