There has been a resurgence of complex oxides of late owing to their ferroelectric and ferromagnetic properties. Although these properties had been recognized decades ago, the renewed interest stems from modern deposition techniques that can produce high quality materials and attractive proposed device concepts. In addition to their use on their own, the interest is building on the use of these materials in a stack also. Ferroelectrics are dielectric materials that have spontaneous polarization in certain temperature range and show nonlinear polarization–electric field dependence called a hysteresis loop. The outstanding properties of the ferroelectrics are due to non-centro-symmetric crystal structure resulting from slight distortion of the cubic perovskite structure. The ferroelectric materials are ferroelastic also in that a change in shape results in a change in the electric polarization (thus electric field) developed in the crystal and vice versa. Therefore they can be used to transform acoustic wav...

Processing, Structure, Properties, and Applications of PZT Thin Films

▪ Abstract The mechanical and acoustic properties of thin films and multilayer assemblies are important both for technological applications of these materials and for basic scientific studies of their physical behavior. Techniques that use optical methods to monitor acoustic waves stimulated in thin films with short pulsed lasers are useful for accurately and nondestructively characterizing the high frequency acoustic physics of these systems. This review briefly summarizes some of these techniques and focuses on a method known as impulsive stimulated thermal scattering or transient grating photoacoustics. It describes the most advanced experimental techniques for performing this measurement and outlines its application to the study of acoustic waveguide modes in a variety of thin films. These measurements, coupled with models for the physics of the modes, can be used to determine intrinsic mechanical properties of materials and structures that occur, for example, in microelectronics and high-frequency ac...

Optical Generation and Characterization of Acoustic Waves in Thin Films: Fundamentals and Applications

We review and critique the recent developments on multifunctional oxide materials, which are gaining a good deal of interest. Recongnizing that this is a vast area, the focus of this treatment is mainly on high-κ dielectric, ferroelectric, magnetic, and multiferroic materials. Also, we consider ferrimagnetic oxides in the context of the new, rapidly developing field of negative-index metamaterials. This review is motivated by the recent resurgence of interest in complex oxides owing to their coupling of electrical, magnetic, thermal, mechanical, and optical properties, which make them suitable for a wide variety of applications, including heat, motion, electric, and magnetic sensors; tunable and compact microwave passive components; surface acoustic wave devices; nonlinear optics; and nonvolatile memory, and pave the way for designing multifunctional devices and unique applications in spintronics and negative refraction-index media. For most of the materials treated here, structural and physical propertie...

Oxides, Oxides, and More Oxides: High-κ Oxides, Ferroelectrics, Ferromagnetics, and Multiferroics

Thin flexible piezoelectric transducers are bonded to or imbedded into oilfield tubular members or structural members. The transducers may be used to telemeter data as acoustic waves through the members. By proper spacing of transducers and phasing of driving signals, the transmitted signals can be directionally enhanced or encoded to improve transmission efficiency. The transducers may be used for health monitoring of the tubular or structural members to detect cracks, delaminations, or other defects. The flexible transducers are very thin so that overall dimensions of tubular or structural members are essentially unchanged by incorporation of the transducers.

Flexible piezoelectric for downhole sensing, actuation and health monitoring

We report on the structural, ferroelectric and optical properties of lead zirconate titanate (PZT) thin films (with a molar ratio of Zr:Ti::65:35) deposited by sol–gel technique on ITO-coated corning 7059 glass substrates. A seed layer of PbTiO3 (0.1mm) was coated by sol–gel on the substrates before depositing PZT. A metal/ferroelectric/metal (MFM) structure was used for electrical property measurements, formed by depositing gold electrodes on top of the film. The films were characterized for C–V, I–V, P–E and optical transmission. Relatively low remnant polarization (Pr ¼ 3:6mC=cm 2 ) was observed for the films. Value of optical band gap was found to be 3.4 eV. The results are discussed.

Structural, ferroelectric and optical properties of PZT thin films

Pb(Zr0.53Ti0.47)O3 (PZT) on diamond is a potentially robust structure for surface acoustic wave (SAW) device applications. We have studied the growth and physical characteristics of PZT on diamond and other substrates by pulsed laser deposition. Under a broad range of processing conditions we explored, PZT deposited directly on diamond is almost exclusively pyrochlore-type, which is nonferroelectric. Growth of ferroelectric perovskite PZT is promoted via the use of a PbTiO3 buffer layer within a narrow window of processing parameters [i.e., P(O2)=100–200 mTorr, T=550–650 °C, 1–2 J/cm2]. Similar results were also obtained for deposition of PZT on Si, Pt-coated Si, and Pt-coated diamond substrates. The dielectric constants of the perovskite PZT films are 500–650 at 1 V and 100 kHz. The piezoelectric coefficients of these films are in the range of 50×10−12–350×10−12 m/V. The SAW velocity of perovskite PZT films is similar to that of highly oriented sputter deposited ZnO films. The acoustic attenuation in per...

Growth and measurements of ferroelectric lead zirconate titanate on diamond by pulsed laser deposition

The invention provides a device comprising an oriented, perovskite PZT layer on a diamond substrate, or other substrates such as silicon or platinum-coated materials. Vapor phase deposition processes are used to deposit a PZT layer onto a perovskite template layer on the substrate. The template layer is more readily deposited in a perovskite structure compared to PZT, and provides for nucleation and growth of the deposited PZT in perovskite form. The vapor phase deposition promotes the oriented structure of the resulting film. The structure is useful in a variety of devices, including surface acoustic wave devices.

Process for fabricating device comprising lead zirconate titanate

Selected-area sol-gel deposition of barium strontium titanate thin films on thermally oxidized silicon through mediation of self-assembled monolayers

PROBLEM TO BE SOLVED: To provide a device which is capable of easily forming an oriented Perovskite layer to show the specified piezoelectric coefficient by depositing a template layer on a substrate of diamond, etc., by a vapor phase deposition method, and depositing a lead zirconate titanate layer thereon by the vapor phase deposition method. SOLUTION: A template layer is deposited on a substrate formed of diamond, silicon, platinum-covered material, etc., by a physical or chemical vapor phase deposition method. The template layer is preferably formed of lead titanate, strontium titanate, barium titanate, etc., of about 0.06-0.12 μm in thickness. A lead zirconate titanate(PZT) layer is deposited thereon by the physical or chemical deposition method. The PZT layer has the dielectric constant of about 500-650 at 1 V and 100 kHz, and is preferably formed to be about 0.1-10 μm in thickness. The PZT layer easily forms an oriented Perovskite layer of about 50×10-12 to 350×10-12 m/V in piezoelectric coefficient through the template layer of Perovskite structure. COPYRIGHT: (C)2000,JPO

Honghua Du

Papers

Growth and measurements of ferroelectric lead zirconate titanate on diamond by pulsed laser deposition

Process for fabricating device comprising lead zirconate titanate

Selected-area sol-gel deposition of barium strontium titanate thin films on thermally oxidized silicon through mediation of self-assembled monolayers

Manufacturing process of device containing lead zirconate titanate