This software tool offers a solution to the limitations of Standard calculation methods (see end of abstract) concerning characterisation of high loss and low sensitivity ferro-piezoelectric ceramic materials.

It can be used to determine a number of material coefficients in complex form (including losses), from the measurement of the frequency dependence of the complex impedance at the electromechanical resonance modes of ferro-piezoelectric ceramics with given geometries:

• Length extensional mode of long rods of bar, poled and excited along their length
• Thickness extensional mode of thin plates or disks, poled and excited along their thickness
• Radial extensional mode of thin disk, poled and excited along its thickness
• Shear mode of a thickness-poled thin plate, excited along its length

The tool comprises a program; a sample set of data; a pdf document with explanations.

The objective of this review is to focus on the processing of ceramics based on sodium potassium niobate (K0.5Na0.5NbO3) as promising candidates for lead-free piezoelectrics. In the first part the review addresses the synthesis of the perovskite solid solution as well as the issue of chemical homogeneity for pure and chemically modified K0.5Na0.5NbO3. The second part covers the sintering and typically encountered bimodal microstructure of K0.5Na0.5NbO3, possible methods of controlling the grain growth and template-assisted grain growth resulting in alkaline niobate single crystals.

Introduction
Chapter 1. ABC of Piezoelectricity and Piezoelectric Materials – N Setter
Chapter 2. Applications of Piezoelectric Materials: an Introductory Review – W Wersing
Chapter 3. Application of Piezoceramics - the Manufacturer Perspective – WW Wolny

Actuators and Multi-Layer Structures: I. Interrelations of Materials and Device Design
Chapter 4. Designing Piezoelectric Actuators – K Uchino
Chapter 5. Performance and Applications of Actuators Based on Multilayered Piezoceramics and Shell Structures – F Claeyssen and R Le Letty
Chapter 6. Piezoelectric Technology for Active Vibration Control – EL Colla and T Morita
Chapter 7. Piezoelectric Transformers – New Perspective – K Uchino, B Koc, P Laoratanakul, and A Vazquez Carazo

Actuators and Multi- Layer Actuators Structures: II. Performance Issues
Chapter 8. Mechanisms for High Strain in Electroactive Actuator Materials – W Ma and LE Cross
Chapter 9. Material Aspects for Reliability and Life Time of PZT Multilayer Ceramics – K Lubitz, C Schuh, T Steinkopff, and A Wolff
Chapter 10. Mechanical and Fracture-Mechanical Properties of Piezoelectric Ceramics and Piezoceramic/ Electrode Interfaces under High Electric Field – GA Schneider
Ultrasonic Transducers
Chapter 11. Piezoelectric Materials for Ultrasonic Medical Diagnostics – M Lethiecq, F Levassort, G Feuillard, and LP Tran-Huu-Hue

Piezoelectrics in MEMS Technologies
Chapter 12. Piezoelectric MEMS with PZT Thin Films: Integration and Application Issues – P Muralt, J Baborowski, and N Ledermann
Chapter 13. Piezoelectric Micro-Electro-Mechanical Systems for Acoustic Applications – Ph Gaucher

Piezoelectrics and Ferroelectrics in Microwave Devices
Chapter 14. Tunable Ferroelectric/piezoelectric microwave devices – SSh Gevorgian
Chapter 15. A Short Introduction to Bulk Acoustic Wave Devices for Telecommunications – P Muralt and R Lanz

Non-Linearities and High Power Applications
Chapter 16. Piezoelectric Materials for High Power Applications: Electromechanical Characterization and Models – P Gonnard
Chapter 17. Piezoelectric Nonlinearity and Hysteresis in Ferroelectric Materials – D Damjanovic and G Robert

Novel Applied Materials
Chapter 18. Lead Free Piezoelectrics – M Demartin Maeder and D Damjanovic
Chapter 19. High Performance, High Temperature Perovskite Piezoelectric Ceramics – TR Shrout, R Eitel, and C Randall
Chapter 20. Relaxor - Based Ferroelectric Single Crystals for Electro - Mechanical Actuators – PW Rehrig, WS Hackenberger, S-E Park, and TR Shrout
Chapter 21. Relaxor Ferroelectric Crystals: Recent Development and Applications – Y (John) Yamashita, Y Hosono, K Harada, and Z-G Ye

New Applied Technologies
Chapter 22. Fabrication of Advanced Functional Electroceramic Components by Solid freeform Fabrication Methods – Safari, J Cesarano III, and PG Clem
Chapter 23. Oriented Films and Ceramics of Relaxor Ferroelectric - PbTiO3 Solid Solutions – S Trolier-McKinstry, E Sabolsky, S Kwon, C Duran, T Yoshimura, J-H Park, Z Zhang, and GL Messing

All profit from the sale of this book is used to support high-school education in Africa

This chapter consists of a short introduction to piezoelectricity and piezoelectric materials aiming to refresh the memory of the reader with elementary basics. The following phenomena, conventions, and properties are defined: piezoelectricity and related properties, piezoelectric coefficients (d, g, e, and h), notation conventions, boundary conditions, coupling coefficient, mechanical quality factor, piezoelectric resonance, frequency constant, acoustic impedance, piezoelectric hysteresis, ferroelectricity, poling and depolarization, domains, domain walls, lattice and domain wall contributions, temperature dependence and aging.

Important piezoelectric materials are briefly reviewed, while pointing to aspects relevant to current and emerging applications: perovskites, PZT, dopants, relaxors, ferroelectric relaxors, layer perovskites, LiNbO3, AlN, other high Tc piezoelectrics, lead free materials, and ferroelectric polymers. Selected issues related to the form of the piezoelectric components are presented: crystals, bulk ceramics, textured ceramics, layered ceramics, composites and thin films. This is done while reviewing structural aspects that are of importance in the use of these components, and comparing between the various forms in relation with applications.

This chapter reviews the application of piezoelectric materials. Following a brief review of the piezoelectric effect, principal transducer structures and designs are shown and special problems such as impedance matching are discussed. Applications based on the direct piezoelectric effect such as igniters, power generators, ultrasound and acceleration sensors, are considered first. Devices based on the inverse piezoelectric effect such as piezoelectric actuators, motors, printer heads, and ultrasound transducers are considered next. Following that, devices based on both effects such as frequency filters, delay lines, piezoelectric transformers, and sonar sensors are reviewed.

In the second part the evolution of different application fields from 1985 onwards is considered, an evolution that resulted from the developments of important material and processing technologies such as special filter ceramics, piezoelectric ceramic tapes, surface acoustic wave technologies, ultrasound transducer, liquid atomizer and ink jet printing technologies. Then the recent development of further application fields based on new technologies such as piezoelectric multilayer ceramics, piezoelectric thin films, and piezoelectric fibers and composites is reviewed. Finally, a new system innovation based on piezoelectric key devices is presented.

Ultrasound has become a widely used technique for medical imaging and blood flow measurements. New modalities such as harmonic imaging and high-resolution imaging are now being integrated in echographic systems. The transducers must be able to operate in these different modes. Consequently, transducer performance requirements are more and more demanding.

The materials used in transducers, in particular those making the piezoelectric element, are also seeing their requirements change. PZT-based ceramics, still widely used, are now often combined with polymers to form piezocomposite structures. The current trend in transducer design is to integrate large quantities of very small elements, forming highly integrated array transducers, and to increase frequency. For this, piezoceramic compositions and fabrication processes are being optimized to obtain higher electromechanical coupling factors, higher dielectric constants, and microstructures of smaller grain size and lower porosity. The recently developed and commercialized relaxor-PZT solid-solutions and the new relaxor PT single crystals with very high electromechanical coupling could allow to significantly increase transducer sensitivity and bandwidth.

Finally, technological issues have an influence on the choice of the piezoelectric element too: an element which is easy to machine and to metallize, and which can be delivered with the net final shape and size, simplifies the transducer fabrication process and is therefore attractive for the manufacture of ultrasonic medical transducers.

The industrial and scientific communities have expressed the need for sensing and actuation over a broad temperature range. This review presents high temperature piezoelectric materials that are commercially available and those that are under development. Key materials, in order of increasing Curie Temperature (Tc) are Pb(Zr,TiO)3, PbTiO3, (Pb,Ba)Nb2O6, Na0.5Bi4.5Ti4O15, and LiNbO3. The maximum operation temperature for sensors is limited by TC combined with the level of sensitivity determined by the piezoelectric voltage coefficient (g) and dielectric loss combined with the level of electrical resistivity. New materials include perovskite layer structured ferroelectric ceramics, which possess the highest known Tcs, and thin film AlN, allowing the potential for operation >>400˚C.

For actuators, high Tc comes with the expense of significantly reduced piezoelectric strain (d33), being further reduced for non-morphotropic phase boundary systems. Recently new high Tc morphotropic phase boundary materials have been developed, as predicted by a perovskite crystal structure tolerance factor relationship. Specifically, compositions based on (1-x)BiScO3–(x)PbTiO3 exhibit piezoelectric activity comparable to PZT, with Tcs greater than 100˚C higher. Furthermore, Tcs > 600˚C are projected in lower tolerance (1-x)Bi(Me)O3–(x)PbTiO3 systems.

In their single crystal form, Relaxor-PbTiO3 ferroelectrics, such as Pb(Zn1/3Nb2/3)O3–PbTiO3 (PZN-PT) and Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) offer great promise for electromechanical actuators. In contrast to polycrystalline materials, such as Pb(Zr,Ti)O3 (PZT), morphotropic phase boundary (MPB) compositions are not essential for high piezoelectric strain. Piezoelectric coefficients (d33) greater than 2000 pC/N and subsequent
strain levels up to > 0.5% with minimal hysteresis are readily found.

Crystallographically, the high strains are achieved for <001> oriented rhombohedral crystals, though <111> in the polar direction.

Ultra-high strain levels up to 1.7%, an order of magnitude larger than those available from conventional piezoelectrics and electrostrictive ceramics can be achieved, being related to an E-field induced phase transformation from rhombohedral to tetragonal.Assuming a macrosymmetry of tetragonal 4mm for the domain engineered <001> oriented rhombohedral crystals, the full set of dielectric, piezoelectric, and elastic coefficients have been determined for selected compositions. In addition to high piezoelectric coefficients, ultra-high electromechanical coupling (k33) > 90% and low dielectric loss (< 1%) are found. Though the elastic stiffness is significantly lower than PZTs, the strain energy density is greater than 6 x 105 J/m3, more than five times higher.

A series of measurement notes are presented, with emphasis placed on the technical nature of the testing methodology, for the determination of key electronic properties for piezoelectric ceramic materials that are used as sensors and actuators. The report is segmented into 'sections' that may be read independently from the rest of the report.

The following measurement issues are discussed:

• Polarisation / Electric field (PE) loop measurements including a discussion of commercial and an in-house constructed system that measures PE loops
• Dielectric measurements at low and high stress application, including some thermal and stress dependency modelling of piezo materials properties, developed at NPL
• Strain measurement techniques developed at CMMT
• Charge measurement techniques suitable for PE loop and other data acquisition
• PE loop measurement and software analysis developed at CMMT and Manchester University

The primary objective of this report is to provide a framework on which the remainder of the testing procedures are to be developed for measurements of piezoelectric properties at high stress and stress rate. These procedures will be the subject of a future publication.