Structure, composition and microwave dielectric properties of bismuth zinc niobate pyrochlore thin films

摘要

(Bi_(1.5)Zn_(0.5))(Zn_(0.5)Nb_(1.5))O_7 (BZN) pyrochlore thin films were deposited onto both Pt/TiO_2/SiO_2/Si and polycrystalline alumina substrates using pulsed laser deposition technique and then post-annealed using rapid thermal processing. The deposition temperature varies from 300 ℃ to 600 ℃, and all the BZN films showed cubic pyrochlore structure after annealing at 650 ℃ for 30 min in air. The influence of the substrate associated with crystal structure is significant in the as-deposited films and disappears after post-annealing. The dielectric properties as a function of frequency up to the microwave frequency in both films were measured by LCR meter and split-post dielectric resonator technique. It is found that the BZN film deposited at 400 ℃ and post-annealed at 650 ℃ shows excellent dielectric properties with low loss in the microwave frequency range. This result indicates that the BZN thin film is a potential microwave material.