X. Y. He

Effect of La content on characterization of PLZT ceramics

Abstract This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb1−xLax(Zr0.40Ti0.60)1−x/4O3, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 μm. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.

Optical and electrical properties of ZnO nanocrystalline textured films prepared by DC reactive magnetron sputtering

ZnO thin films were deposited by DC reactive magnetron sputtering using a metal zinc target. The crystallinity microstructure and surface morphology of ZnO thin films were investigated by X- ray diffraction (XRD) and scanning electron microscopy (SEM). The composition of ZnO thin film was characterized by XPS. The optical properties of ZnO thin film were obtained by spectroscopy ellipsometry and UV-VIS spectrometry. The optical bandgap was found to be 3.29eV of direct-transition type. The low frequency (1kHz- 100kHz) dielectric properties of ZnO thin film were also discussed. The dielectric constant and dielectric loss at 10kHz are 13.4 and 0.03 respectively.

DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF Mn DOPED (K, Na)0.96Sr0.02NbO3 CERAMICS

ABSTRACT Dense lead free ceramics with composition of (K0.5Na0.5)0.96Sr0.02Nb1-x MnxO3 (x = 0,0.01,0.02,0.03,0.04) were successfully prepared by conventional mixed oxide method, and their dielectric and piezoelectric properties have been investigated. The X-ray diffraction patterns indicated phase transition from peroveskite structure with orthorhombic symmetry to pseudo-tetragonal symmetry with increasing Mn content. Low loss tangent and relative high planar electromechanical coupling factor were obtained at x = 0.02 by the introduction of Sr and Mnion. The main parameters for the composition of x = 0.02 are: ϵ33 T/ϵ0 = 479, d33 = 121 kp = 41%, Qm = 298, tanδ = 1.6%, Tc = 391°C. The rates of resonant frequency variation, αfr, and planar coupling factor variation, αkp, with temperature 80°C are −1.85% and +1.19%, respectively. This material may be suitable for applications in ultrasonic transducers.

EPITAXIAL GROWTH OF PLZT THIN FILM ON SrTiO3 SUBSTRATE BY SPUTTERING METHOD

ABSTRACT PLZT thin films were prepared on SrTiO3 substrate by RF magnetron sputtering method. The electrical measurements were conducted on PLZT films in metal-ferroelectric-semiconductor capacitor configuration (MFS). The PLZT thin films annealed at 650°C showed well-saturated hysteresis loops with remanent polarization and coercive electric field values were 0.3 μ C/cm2 and 36 KV/cm respectively. The relationship between the orientation of thin film and thermal treating condition was discussed. The PLZT thin films with a thickness of 1.5 um were epitaxially grown on SrTiO3 substrate successfully.

THE MICROSTRUCTURE AND PROPERTIES OF DYSPROSIUM IONS DOPED PLZT CERAMICS

ABSTRACT The polycrystalline 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 ceramic method. Dysprosium concentration, x, was varied from 0 to 0.5. Effects of dysprosium substitution on structural and optical properties are report here. All the samples have single phase with tetragonal structure, and the tetragonality was increased with Dy3+ content increased. The Raman spectra indicated that Dy distribution in A or B site in PLDZT ceramics with different doping amounts.

Preparation of PZT fine powders for fabricating PZT thick films

Abstract A new process for preparation of PZT fine powder was proposed. By adding acetone and ammonia water to the precursor solution at suitable stages, nanosized powders with minimum agglomeration can be obtained. The effect of these additives on the powder preparation is analyzed according to the principle of the growth dynamics and the agglomeration mechanism of powders. Uniform powders with a perfect perovskite-type PZT phase have been obtained and the size of the powder is in the range of 100–200nm. Pb(Zr.40Ti.60)O3 thick film with 10 μm thickness and excellent properties have been successfully prepared by mixing PZT powders into a PZT sol-gel solution to form a 0/3 ceramic-ceramic composition.