Papers by Author: Ping Sun Qiu

Abstract: A new process was developed for fabrication of multiferroic 1-3 type nanostructured composite films. In this process, eletrodeposition method was adopted to prepare the arrays of cobalt nanowires as ferromagnetic composition. The images, phase structure and magnetic properties were characterized by SEM, XRD and VSM, respectively. The results showed that applying magnetic field during electrodepostion process could improve the alignment and height uniformity of nanowires arrays, inducing (002)-orientation growth. The PZT (53/47) precursor solution prepared for ferroelectric composition was infiltrated the spaces between nanowires. After annealed at 700 °C for 20 min, the 1-3 type multiferroic composite film was achieved. Preliminary results show this technique to have the potential to become a practical fabrication process for 1-3 type multiferroic composite films.

Abstract: Ba0.6Sr0.4TiO3 materials doped with boron family Al3+, Ga3+ and In3+ are prepared by a ceramic process. The specimens possess condense microstructures. A low dielectric loss is achieved in the sample doped with In3+. Dielectric constants increase with decrease of the radii of doped ions. The results are discussed with respect to the interaction between oxygen ions and ions at B-site in ABO3 perovskite, which is revealed by Fourier transform infrared spectrum.

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: Amorphous and crystalline (Zr0.8,Sn0.2)TiO4 （ZST） thin films deposited on Si(100) substrates have been prepared by a sol-gel process. The crystal structure and surface morphologies of the thin films have been studied by X-ray diffraction and atomic force microscopy. The crystalline ZST films on Si(100) substrata with a (111) orientation The refractive index n and extinction coefficient k of the amorphous and crystalline thin films were obtained by spectroscopy ellipsometry as a function of phone energy in the range from 0.7 to 5.4 eV. The absorption edges for amorphous and crystalline ZST are 3.83 and 3.51eV of indirect–transition type respectively.