Study on the preferred orientations of nearly cubic PZT particles synthesized by hydrothermal methods using TiCl3 reagent

Various parameters such as gel composition, aging, organic additive, and heating method affected the preferred orientation of nearly cubic PZT particles that were prepared by hydrothermal methods using TiCl₃ as a Ti³⁺ source, at relatively low temperatures of 100-140 °C. The newly found synthetic conditions could be used to develop specially orientated PZT particles, which may be useful in growing oriented films, for example, by electrophoretic deposition.     

Effect of heating rate on dielectric and pyroelectric properties of double doped PZT

Abstract

Double doped lead zirconium titanate (PZT) was synthesised by solid state reaction method. Calcination and sintering was carried out at various heating rates in order to study the effect of heating rate on the extent of phase formation of double doped PZT. Furthermore, the effect of heating rate on dielectric and pyroelectric properties was also investigated. Rhombohedral perovskite phase was confirmed in the double doped PZT samples. Quantitative X-ray diffraction (XRD) analysis suggests that the extent of PZT formation decreases beyond 8°C min^?1 heating rate. The crystallite and grain sizes calculated from Scherrer's equation and field emission scanning electron microscope (FE-SEM) photographs respectively show the decreasing behaviour with increasing heating rate. Dielectric and pyroelectric properties show the increasing behaviour up to 8°C min^?1 and decreasing behaviour beyond this heating rate.     

Dielectric breakdown in high-ε films for ulsi DRAMs: III. Leakage current precursors and electrodes

Abstract

A somewhat qualitative review of leakage currents J(V,t) in perovskite oxides is presented. It is stressed that space-charge-limited currents (SCLCs) are not alternatives to ionic conduction, Schottky emission, Poole-Frenkel, or Fowler-Nordheim tunneling, but can occur whenever currents due to any of those mechanisms reach a certain threshold and are no longer limited by the details of the metal electrode-ferroelectric interface. Standard metal-semiconductor band models that exclude surface states fail qualitatively to account for the experimental dependences of leakage currents and breakdown voltages on electrode work function; the correct model is metal-n-p-n-metal, with surface donor-state trapping. A discussion of conduction properties in these materials is presented from an ionic conductor viewpoint.     

The PZT system (PbTixZr1−xO3, 0≤x≤1.0): High temperature X-ray diffraction studies. Complete x-T phase diagram of real solid solutions (Part 3)

Based on high temperature x-ray diffraction studies of the PZT system (PbTi_xZr_1−xO₃, 0.0≤x≤1.0) the complete x-T phase diagram of solid solutions is built, which exhibits peculiar properties due to the real structure of ceramics:     

Ferroelectric SrBi 2 Nb 2 O 9 Thin Films by Aqueous Chemical Solution Deposition

SrBi 2 Nb 2 O 9 (SBN) thin films on a Pt/Ti/SiO 2 /Si substrate were prepared by aqueous chemical solution deposition. The precursor solution was synthesized by means of an 'aqueous solution-gel method', starting with stable, inexpensive and easily available inorganic salts which are dissolved in an aqueous solution of chelating or coordinating ligands (acetates and citrates). Afterwards the synthesized precursor was spin-coated. However, problems arose as a consequence of insufficient 'wetting' of the substrate surface by the aqueous solution (poor film-substrate adhesion). Instead of improving surface adhesion by the addition of a surface-wetting reagent, a new strategy was developed: prior to spin-coating the platinum surface characteristics were modified using a UV/ozone technique. In this way the precursor solution was not chemically changed. Wetting/wettability was verified by means of contact angle measurements. A uniform, three-layer thin film with a total thickness of about 200 nm was obtained after thermal treatment, as could be verified using SEM and XRD.     

Effect of rare earth doping on sol-gel derived PZT thin films

We have studied the effect of rare earth dopants (Nd, Gd and Ce) on the phase formation behavior and electrical properties of sol-gel derived Pb_1.05(Zr_0.53Ti_0.47)O₃ thin films. In all these films the perovskite phase is obtained up to 5 at% doping and beyond that pyrochlore phase was found to coexist with the perovskite phase. Ce and Gd doping(1-2 at%) exhibited improved ferroelectric and dielectric properties as compared to the undoped PZT films. Nd doping (2 at%) was found to be effective to increase the retained switchable polarization of undoped PZT from 63% to 84%. The transition temperature of undoped PZT film was found to be reduced with Nd doping. The Nd doped films also exhibited typical relaxor behavior and a diffuse phase transition, characteristic of the relaxor material. Introduction of Nd into the PZT lattice probably introduces disorder in the B site of ABO₃ lattice which causes the observed relaxor behavior     

DEVICE DESIGN FOR THE NOVEL HANDWRITING RECOGNITION SYSTEM

ABSTRACT

A microelectromechanical systems-based handwriting system device was designed. We proposed an ominidirectional acoustical sensor microarray which can offer isotropic directional sensitivity with a high radiation acoustic power when it as a transmitter and a high array spatial gain (AG) when it as a receiver. It has been designed for use in the novel handwriting recognition system to attain a large writeable scale and to write in any direction. The proposed array device based on novel ferroelectric thin film has excellent performance, miniature size and high reliability, and could be fabricated with conventional integrated circuit process.     

PbZr0.52Ti0.48O3陶瓷材料的微结构和疲劳性能研究

先给出了PbZr0.52Ti0.48O3(PZT)陶瓷材料在低温下变温XRD分析结果，证明了超晶格的出现与材料的微结构变化有关。测试了该样品在低温下的疲劳性能。与超晶格出现以前相比，其疲劳寿命有所提高，这对于PZT材料的应用有着重要的意义。     

Bi~（3＋）、K~＋、OH~－离子对水热合成PZT结晶末化学性质影响的研究

本文研究了水热条件下Ｂｉ３＋、Ｋ＋、ＯＨ－对水热合成ＰＺＴ结晶粉末化学性质的影响，并用了ＸＲＤ、ＥＰＭＡ和ＳＥＭ及原子吸收光谱分析，对水热合成ＰＺＴ结晶粉末及其烧结体进行了分析     

Partial Discharge Signal Detection by Piezoelectric Ceramic Sensor and The Signal Processing

Partial discharge (PD) in an insulator or on surface of defective conductor emits acoustic wave transmitting through an air or an insulator. The acoustic wave between 20 kHz and several hundred of kHz can be detected by piezoelectric ceramic sensor that converts the acoustic wave into an electrical signal. Piezoelectric ceramic sensor has either the wide resonant band or the local resonant band depending on the ceramic material or the various combinations of each different component in the manufacturing process. This paper presents the piezoelectric ceramic sensor with 0.95 PZT–0.05 PMNS that yields the piezoelectric properties of high k_p, high Q_m. It has the frequency characteristics of local resonant band, such that it can be applied to PD detection. We have demonstrated the properties of the proposed piezoelectric ceramic sensor by comparing with the conventional electrical PD detector. Quantitative analysis is accomplished by comparing the -q_max from a PD detector and the -v_max from the proposed sensor while -n distributions are the same for both the conventional phase-resolved PD analysis method and the proposed one.