Piezoelectricity and Ferroelectricity

Piezoelectric properties are found in NH4H2PO4 and in the quartz form of AIPO4. The former has been used in sonar devices. Ferroelectric properties of KH2PO4 and related salts are well known and have been recognised since 1935 [73] (Chapter 13.1). 

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Potassium Phosphates. The K2O—P20 —H2O system parallels the sodium system in many respects. In addition to the three simple phosphate salts obtained by successive replacement of the protons of phosphoric acid by potassium ions, the system contains a number of crystalline hydrates and double salts (Table 7). Monopotassium phosphate (MKP), known only as the anhydrous salt, is the least soluble of the potassium orthophosphates. Monopotassium phosphate has been studied extensively owing to its piezoelectric and ferroelectric properties (see Ferroelectrics). At ordinary temperatures, KH2PO4 is so far above its Curie point as to give piezoelectric effects in which the emf is proportional to the distorting force. There is virtually no hysteresis. 

Alkaline-Earth Titanates. Some physical properties of representative alkaline-earth titanates ate Hsted in Table 15. The most important apphcations of these titanates are in the manufacture of electronic components (109). The most important member of the class is barium titanate, BaTi03, which owes its significance to its exceptionally high dielectric constant and its piezoelectric and ferroelectric properties. Further, because barium titanate easily forms solid solutions with strontium titanate, lead titanate, zirconium oxide, and tin oxide, the electrical properties can be modified within wide limits. Barium titanate may be made by, eg, cocalcination of barium carbonate and titanium dioxide at ca 1200°C. With the exception of Ba2Ti04, barium orthotitanate, titanates do not contain discrete TiO ions but ate mixed oxides. Ba2Ti04 has the P-K SO stmcture in which distorted tetrahedral TiO ions occur. 

Fig. 5.19. Shock-induced volume polarizations have been observed in a wide range of solids due to a number of different physical phenomena, including piezoelectricity and ferroelectricity. The signals observed from polymers and ionic crystals are not due to established phenomena, and are described as due to shock-induced polarization effects.

Crosslinked LC elastomers (Figure 19d) are very promising for piezoelectric and ferroelectric applications, and also as non-linear optic materials. The first synthetic step to such materials is the preparation of usual side chain or combined LC copolymers doped with a small part of side chains containing a polymerizable >C=C< double bond at the end (Figure 23 shows a particular example of a crosslinkable LC polymer64). The copolymer can be further photocrosslinked, giving an elastic polymer film which reveals... 

Leslie E., Cross, Dielectric, piezoelectric and ferroelectric components. Ceramic Bulletin. 63 (1984) pp. 585-590. 

The discussion in this section is applicable to any polar solid (i.e., one that has a permanent dipole) in which relaxation of the permanent dipoles occurs. In principle this approach could be applicable to piezoelectric and ferroelectric solids at temperatures above their transition temperature as well (see next chapter). However, the same response, as shown in Fig. 14.11, can also occur as a result of heavily damped resonance. This is easily seen in Fig. 14.7a as /. which is a measure of the damping, increases, the resultant resonance curves become flatter. Experimentally it is not easy to distinguish between the two phenomena. 

Handbook of advanced dielectric, piezoelectric and ferroelectric materials Synthesis, properties and applications... 

Bowen, C.R., Kim, H.A., Weaver, P.M., Dunn, S., 2014. Piezoelectric and ferroelectric materials and structures for energy harvesting applications. Energy Environ. Sci. 7,25-44. 

Hattori, X, Takahashi, Y, lijima, M., Fukada, E., 1996. Piezoelectric and ferroelectric properties of polyurea-5 thin films prepared by vapor deposition polymerization. J. Appl. Phys. 79,1713-1721. 

Piezoelectricity and ferroelectricity are the result of electric dipole effects that are due to ions shifting from their initial positions in the lattice. This effect, which is strongly structure-dependent, was discussed above. Pyroelectric materials have permanent electric dipole moments, their magnitude varying with temperature. In infrared detectors, use is made of the ferroelectric phase transitions in perovskites. 

Describe the thermal and electromechanical behavior of piezoelectric and ferroelectric compounds. 

Damjanovic, D. (2005) Hysteresis in piezoelectric and ferroelectric materials, in Science of Hysteresis (eds G. Bertotti and I. Mayergoyz), Elsevier,... 

Bolten, D., Bdttger, U., Waser, R. 2004. Reversible and irreversible piezoelectric and ferroelectric response in ferroelectric ceramics and thin films. Journal of the European Ceramic Society 24,725-732. 

Barium titanate is a crystalline ceramic compound with outstanding diaelectric, piezoelectric, and ferroelectric properties. It is used in capacitors and as a piezoelectric transducer. 

Solid solutions of lead zirconate (PbZr03) and lead titanate (PbTi03) are denoted by the chemical formula Pb(Zr,Ti)03, and are unique materials that exhibit both piezoelectricity and ferroelectricity. They are often referred to by the abbreviation PZT. 

The research field is also very wide. It stretches from the properties of piezoelectric and ferroelectric materials, their manufacture, up to measurement techniques and practical applications. As a result we can expect in the near future the development of many new commercial products for industry and mihtary. 

Barium Titanate. BaTi03, m.p. 1618°C. Made by heating a mixture of barium carbonate and titania at 1300-1350°C. Because of its high dielectric constant (1350-1600 at 1 MHz and 25 C) and its piezoelectric and ferroelectric properties, it finds use in electronic components its Curie temperature is 120-140°C. The properties can be altered by the... 

Wood GO, Moyer ES (1991) A review and comparison of adsorption isotherm equations used to correlate and predict organic vapor cartridge capacities. Am Ind Hyg Assoc J 52 235-242 Yanagitani T, Kiuchi M, Matsukawa M, Watanabe Y (2007) Characteristics of pure-shear mode BAW resonators consisting of (1120) textured ZnO films. IEEE Trans Ultrason Eerroelectr Freq Control 54 1680-1686 Ye ZG (ed) (2008) Handbook of advanced dielectric piezoelectric and ferroelectric mater synthesis characterization and applications. Woodhead, Cambridge... 

Piezoelectric and Ferroelectric Properties of Ln2Tl207 Thin Films... 

Piezoelectric and Ferroelectric Properties ofLn2Tifij Thin Films 1245... 

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