Papers by Author: Yong Zhang

Abstract: PLZT (9/65/35) thin films on sapphire (001) substrates with thickness of 0.1 ~ 0.9 µm were prepared by a metal-organic decomposition (MOD) process. All the films present highly (110)-preferred orientation independent of the film thickness. The microstructure of the films was investigated. The influence of film thickness on optical properties of PLZT films was examined and analyzed. As the film thickness is increased, the absorption edge of the film is shifted to longer wavelength; the optical band gap Eg is increased slightly. The refractive index at 510nm determined from optical transmission spectra also shows an increasing tendency as film thickness increasing. Great stress aggregated during the film preparing process is thought to be an important reason which results in the variations of optical properties of the films with different thickness.

Abstract: La-modified PZN-PZT compositions with representative formula Pb1-0.7xLa0.7x(Zn1/3Nb2/3)0.3- (Zr0.55Ti0.45)0.7(1-x/4)O3 were prepared by the columbite precursor method. La content, x, was varied from 0 to 8mol%. Effects of La doping on microstructure, dielectric and piezoelectric properties were investigated. The results showed that in present system La doping promotes the formation of pyrochlore phase and the phase shifted from rhombohedral to tetragonal structure with increasing La content. It was also found that La doping makes dielectric permittivity maximum decrease and the degree of diffuse phase transition enhance. Appropriate amount of La doping could improve the piezoelectric properties.

Abstract: Polycrystalline dysprosium (Dy) doped PLZT ceramics with compositional formula [Pb0.88 (La1-xDyx)0.12](Zr0.40 Ti0.60)O3] were prepared by hot-pressed solid-state method. Dy3+ concentration x varied from 0 to 0.5. All samples present single phase with tetragonal structure and the tetragonality was increased with increasing Dy3+ content. The Raman spectra indicated that Dy3+ ions could be distributed in both A and B site of ABO3 perovskite structure depending on the doping amounts.