**Abstract**

The piezoelectric effect is extensively encountered in nature and many synthetic materials. Piezoelectric materials are capable of transforming mechanical strain and vibration energy into electrical energy. This property allows opportunities for implementing renewable and sustainable energy through power harvesting and self-sustained smart sensing in buildings. As the most common construction material, plain cement paste lacks satisfactory piezoelectricity and is not efficient at harvesting the electrical energy from the ambient vibrations of a building system. In recent years, many techniques have been proposed and applied to improve the piezoelectric capacity of cement-based composite, namely admixture incorporation and physical. The successful application of piezoelectric materials for sustainable building development not only relies on understanding the mechanism of the piezoelectric properties of various building components, but also the latest developments and implementations in the building industry. Therefore, this review systematically illustrates research efforts to develop new construction materials with high piezoelectricity and energy storage capacity. In addition, this article discusses the latest techniques for utilizing the piezoelectric materials in energy harvesters, sensors and actuators for various building systems. With advanced methods for improving the cementations piezoelectricity and applying the material piezoelectricity for different building functions, more renewable and sustainable building systems are anticipated.

**Keywords:** piezoelectric effect, ferroelectricity, actuators, sensors, buzzers

#### **1. Introduction**

Technical application of Piezoelectricity phenomenon first discovered by Pierre and Jacques curie and Jacques curie in 1880 [1] and thereafter soon understood from the crystallographic point of view had a very slow start because for decades only a few suitable materials were available. In spite of their small piezoelectric effect, quartz crystals continue to dominate as components for frequency control since the early days of radio engineering [2], this is due to their extremely sharp resonance curves, which are stable with respect to temperature and aging. The first ferroelectric material, Rochelle Salt [3] was found out to the suitable for broadband applications in the year 1920.Stability problems encountered with these crystals,

which are produced from aqueous solutions, restrict their application to phonograph pick-ups.

Additional piezoelectric constants which occasionally used are 'e' which relates

For ceramics and crystals the elastic, dielectric and piezoelectric constants may

where d33 ¼ ð Þ ∂D3*=*∂T3 <sup>E</sup> ¼ ð Þ ∂S3*=*∂E3 <sup>T</sup> d31 ¼ ð Þ ∂D3*=*∂T1 <sup>E</sup> ¼ ð Þ ∂S1*=*∂E3 <sup>T</sup>

Possibly the best single measurement of the strength of a piezoelectric effect is the electromechanical coupling factor K. When an electric field is applied, it measures the fraction of the electrical energy converted to mechanical energy (or vice versa when a crystal or ceramic is stressed). The actual relationship is in

> *<sup>K</sup>*<sup>2</sup> <sup>¼</sup> *Electrical energy converted to mechanical energy Input electrical energy*

> *<sup>K</sup>*<sup>2</sup> <sup>¼</sup> *Mechanical energy converted to electrical energy Input mechanical energy*

The piezoelectric, elastic and dielectric constants of poled ceramics are strongly temperature dependent. Heating through the Curie point destroys the effect of poling and causes the piezoelectric properties to disappear [4]. If the sample is heated to just below the Curie point the piezoelectric properties are degraded. A remanant piezoelectric effect produced by polling an initially random orientation ceramic is a strong evidence for ferroelectricity 90<sup>0</sup> walls contribute to the piezoelectric effect since their movement is accompanied by dimensional change and not 1800 walls because there will be no dimensional change [5]. Ferroelectric materials with high Curie temperature are highly desirable to construct transducers for high

Certain crystals become electrically polarized (i.e electric charges appear on their surfaces) when stressed. This phenomenon discovered in 1800 by Pierre and J. Curie is called the piezoelectric effect and the crystals as the piezoelectric crystals

Quartz, rochelle salt, tourmaline are the familiar piezoelectric substances.

differ along different axes. For this reason, they are expressed in tensor form. The hydrostatic strain constant dh is related to d33 and d31 as follows:

T ¼ �eE (5) T ¼ �hS (6)

d ¼ ð Þ ∂S*=*∂E <sup>T</sup> ¼ ð Þ ∂D*=*∂T <sup>E</sup> (7) <sup>g</sup> ¼ �ð Þ <sup>∂</sup>E*=*∂<sup>T</sup> <sup>D</sup><sup>¼</sup> ð Þ <sup>∂</sup>S*=*∂<sup>D</sup> <sup>T</sup> (8) <sup>e</sup> <sup>¼</sup> ð Þ <sup>∂</sup>T*=*∂<sup>E</sup> <sup>S</sup><sup>¼</sup> ð Þ <sup>∂</sup>D*=*∂<sup>S</sup> <sup>E</sup> (9) <sup>h</sup> ¼ �ð Þ <sup>∂</sup>T*=*∂<sup>D</sup> <sup>S</sup><sup>¼</sup> ð Þ �∂E*=*∂<sup>S</sup> <sup>D</sup> (10)

dh ¼ 2d31 þ d33 (11)

stress T to field E, and 'h' which relates strain S to field E.

Actual definitions are.

*Piezoelectricity and Its Applications*

*DOI: http://dx.doi.org/10.5772/intechopen.96154*

terms of K<sup>2</sup>

temperature piezoelectric applications.

**2. Piezoelectricity**

**73**

Over the past period the spheres of application of piezoelectric materials in modern techniques have been considerably enlarged. In this relation the requirements to their properties are continuously growing. A great number of the piezoelectric materials have been developed in several countries, yet research in this field is still in active. The efforts of researchers are concentrated on the problem of purposeful development of the materials with desirable combination of their properties. The wide spread application of the piezoelectric effect is based on ferroelectric ceramic materials can be attributed to three main facts:


At present piezoelectric materials based on Barium Titanate (BaTiO3). Lend Zirconate-Lead Titanate (PZT) solid solutions and multi component solid solutions relating to the Perovskite type crystal structure and containing, as a rule, lead titanate or lead zirconate, are mainly used [3].

Most of the improvements in the properties for particular application in the piezoceramics have been achieved either by partially replacing the constituent atoms by other atoms or doping with a small quantity of purity additives. Broadly speaking, all these methods may be considered to the control the ceramic characteristic properties by impurity doping.

Piezoelectricity is the additional creation of an electric charge by the applied stress; this is the direct piezoelectric effect. The charge is proportional to the force, and it is therefore of opposite sign for compression and tension. In terms of dielectric displacement D (charge Q per unit area A) and stress T, it may be written as.

$$\mathbf{D} = \mathbf{Q}/\mathbf{A} = \mathbf{d}T \tag{1}$$

There is a converse effect. An applied field E produces a proportional strain S, expansion or contraction depending on polarity.

$$\mathbf{S} = \mathbf{d} \mathbf{E} \tag{2}$$

Therefore, the piezoelectric constant 'd' (Piezoelectric strain coefficient) which is numerically identical for both direct and converse effects.

$$\mathbf{d} = \mathbf{D}/\mathbf{T} = \mathbf{S}/\mathbf{E} \tag{3}$$

Another frequently used piezoelectric constant is g (piezoelectric voltage coefficient), which give the field produced by a stress and is related to the 'd' constant by the permittivity (ε).

$$\mathbf{g} = \mathbf{d}/\mathbf{e} \tag{4}$$

Additional piezoelectric constants which occasionally used are 'e' which relates stress T to field E, and 'h' which relates strain S to field E.

$$\mathbf{T} = -\mathbf{e}\mathbf{E}\tag{5}$$

$$\mathbf{T} = -\mathbf{h}\mathbf{S} \tag{6}$$

Actual definitions are.

which are produced from aqueous solutions, restrict their application to phono-

Over the past period the spheres of application of piezoelectric materials in modern techniques have been considerably enlarged. In this relation the requirements to their properties are continuously growing. A great number of the piezoelectric materials have been developed in several countries, yet research in this field is still in active. The efforts of researchers are concentrated on the problem of purposeful development of the materials with desirable combination of their properties. The wide spread application of the piezoelectric effect is based on ferroelec-

2.Ceramics can be produced cost effectively. Most of these materials are either impossible or at best very difficult to produce in mono crystalline form.

3.Ceramic materials offer a high degree of variation concerning geometrical shaping on the one hand and physical properties on the other hand by virtue of mixed-crystal formation, creation of differing grain structures, and interaction

At present piezoelectric materials based on Barium Titanate (BaTiO3). Lend Zirconate-Lead Titanate (PZT) solid solutions and multi component solid solutions relating to the Perovskite type crystal structure and containing, as a rule, lead

Most of the improvements in the properties for particular application in the piezoceramics have been achieved either by partially replacing the constituent atoms by other atoms or doping with a small quantity of purity additives. Broadly speaking, all these methods may be considered to the control the ceramic charac-

Piezoelectricity is the additional creation of an electric charge by the applied stress; this is the direct piezoelectric effect. The charge is proportional to the force, and it is therefore of opposite sign for compression and tension. In terms of dielectric displacement D (charge Q per unit area A) and stress T, it may be written as.

There is a converse effect. An applied field E produces a proportional strain S,

Therefore, the piezoelectric constant 'd' (Piezoelectric strain coefficient) which

Another frequently used piezoelectric constant is g (piezoelectric voltage coefficient), which give the field produced by a stress and is related to the 'd'

D ¼ Q*=*A ¼ dT (1)

S ¼ dE (2)

d ¼ D*=*T ¼ S*=*E (3)

g ¼ d*=*ε (4)

tric ceramic materials can be attributed to three main facts:

of various ferroelectric or non- ferroelectric phases.

titanate or lead zirconate, are mainly used [3].

expansion or contraction depending on polarity.

is numerically identical for both direct and converse effects.

teristic properties by impurity doping.

constant by the permittivity (ε).

**72**

1.The Piezoelectric effect particularly large in the ferroelectrics.

graph pick-ups.

*Multifunctional Ferroelectric Materials*

$$\mathbf{d} = (\partial \mathbf{S} / \partial \mathbf{E})\_{\mathbf{T}} = (\partial \mathbf{D} / \partial \mathbf{T})\_{\mathbf{E}} \tag{7}$$

$$\mathbf{g} = (-\partial \mathbf{E}/\partial \mathbf{T})\_{\mathrm{D} =} (\partial \mathbf{S}/\partial \mathbf{D})\_{\mathrm{T}} \tag{8}$$

$$\mathbf{e} = (\partial \mathbf{T} / \partial \mathbf{E})\_{\mathbf{S}=} (\partial \mathbf{D} / \partial \mathbf{S})\_{\mathbf{E}} \tag{9}$$

$$\mathbf{h} = (-\partial \mathbf{T}/\partial \mathbf{D})\_{\mathbf{S}=} (-\partial \mathbf{E}/\partial \mathbf{S})\_{\mathbf{D}} \tag{10}$$

For ceramics and crystals the elastic, dielectric and piezoelectric constants may differ along different axes. For this reason, they are expressed in tensor form.

The hydrostatic strain constant dh is related to d33 and d31 as follows:

$$\mathbf{d}\_{\mathbf{h}} = 2\mathbf{d}\_{31} + \mathbf{d}\_{33} \tag{11}$$

$$\text{where } \mathbf{d}\_{33} = (\partial \mathbf{D}\_{3}/\partial \mathbf{T}\_{3})\_{\mathbf{E}} = (\partial \mathbf{S}\_{3}/\partial \mathbf{E}\_{3})\_{\mathbf{T}}$$

$$\mathbf{d}\_{31} = (\partial \mathbf{D}\_{3}/\partial \mathbf{T}\_{1})\_{\mathbf{E}} = (\partial \mathbf{S}\_{1}/\partial \mathbf{E}\_{3})\_{\mathbf{T}}$$

Possibly the best single measurement of the strength of a piezoelectric effect is the electromechanical coupling factor K. When an electric field is applied, it measures the fraction of the electrical energy converted to mechanical energy (or vice versa when a crystal or ceramic is stressed). The actual relationship is in terms of K<sup>2</sup>

$$K^2 = \frac{\text{Electrical energy converted to mechanical energy}}{\text{Input electrical energy}}$$

$$K^2 = \frac{\text{Mechanical energy converted to electrical energy}}{\text{Input mechanical energy}}$$

The piezoelectric, elastic and dielectric constants of poled ceramics are strongly temperature dependent. Heating through the Curie point destroys the effect of poling and causes the piezoelectric properties to disappear [4]. If the sample is heated to just below the Curie point the piezoelectric properties are degraded. A remanant piezoelectric effect produced by polling an initially random orientation ceramic is a strong evidence for ferroelectricity 90<sup>0</sup> walls contribute to the piezoelectric effect since their movement is accompanied by dimensional change and not 1800 walls because there will be no dimensional change [5]. Ferroelectric materials with high Curie temperature are highly desirable to construct transducers for high temperature piezoelectric applications.

#### **2. Piezoelectricity**

Certain crystals become electrically polarized (i.e electric charges appear on their surfaces) when stressed. This phenomenon discovered in 1800 by Pierre and J. Curie is called the piezoelectric effect and the crystals as the piezoelectric crystals Quartz, rochelle salt, tourmaline are the familiar piezoelectric substances.

The inverse effect–that these crystals become strained when polarized has also been observed.

The phenomenon of piezoelectricity was discovered just over a hundred years ago by the Curie brothers, Pierre and Jaques. The science of Piezoelectricity has proceeded at an uneven face in these one hundred years. Periods of rapid progress have been followed by periods of slow development and sometimes even by periods of no development (Incidentally, this is characteristic of all branches of science). Every time that piezoelectricity has appeared to be exhausted as a science, the discovery of new piezoelectric effects or new piezoelectric materials initiated a new stage of rapid development and opened up new areas for the application of piezoelectricity. Piezoelectricity is currently enjoying a great resurgence in both Funda-

Piezoelectricity is one of the basic properties of crystals, ceramics polymers and

(**Figure 1**) the piezoelectric constants describing the linear relationship form a third order tensor. A simplified mathematical formulation of the piezoelectric effect is given below. More detail treatments of the piezoelectric effect and Converse effect

It should be noted that the piezoelectric effect is strongly linked to the Crystal symmetry. All crystals are arranged into 32 point groups. Crystals belonging to the 11 centro symmetric point groups cannot show a piezoelectric effect. Crystals belonging to the non centro symmetric point group O also do not exhibit a piezoelectric effect. Nearly all other non metallic crystals belonging to the remaining 20 point groups exhibit a piezoelectric effect of some magnitude, although some of the

<sup>i</sup> þ jkEdijk Tjk (12)

The piezoelectric phenomenon can be described as.

Pi <sup>¼</sup> <sup>P</sup><sup>0</sup>

liquid crystals. There are several ways to describe the piezoelectric effect [9]. Perhaps the most common definition is that a material is piezoelectric if the application of an external mechanical stress causes the development of an internal dielectric displacement. This displacement is manifested as an internal electric polarization or a surface electric charge Because of the way in which the elastic stress and dielectric displacement transform during coordinate axis rotation

mental Research and Technical applications.

*Piezoelectricity and Its Applications*

*DOI: http://dx.doi.org/10.5772/intechopen.96154*

can be found in texts.

effects are very small.

**Figure 1.** *Piezoelectric effect.*

**75**

Piezoelectric strains are very small, and the corresponding electric fields are very large. In Quartz for example a field of 1000 V/cm produces a strain of the order of 10�<sup>7</sup> . Conversely small strains can produce large electric fields.

To understand the origin of the piezoelectric effect, the distribution of the ionic charges of a crystal about their lattice sites. Normally, the distribution is symmetrical, and the internal electric field is zero. But when the crystal is stressed, the charges are displaced. In a piezoelectric crystal this displacement distorts the original charge distribution in such a way that it is no longer symmetrical - for a quartz crystal. A net polarization results in such crystals and when observing the piezoelectric effect. In other crystals, on the other hand, the distribution of charges maintains its symmetry even after the displacement - for a non piezoelectric crystal. Such crystals exhibit no net polarization and hence no piezoelectric effect [6].

It follows that the piezoelectric effect is related to crystal symmetry. The symmetry element involved is essentially the center of inversion. A crystal can exhibit piezoelectric effect only if its unit cell lacks a center of inversion. This is because when there is no center of inversion, only then the charge distribution is distorted so as to produce polarization. However if the center of inversion is present, there is no charge distortion hence no polarization.

It can be proved that of the 32 crystal classes, 21 are non centro symmetrical but since one of these 21 is highly symmetric in other respects, it is piezoelectrically excluded, leaving only 20 piezoelectric classes. However, all crystals belonging to these 20 classes are not observably piezoelectric - in some crystals the piezoelectric effects are too small to be detectable. Thus, the lack of inversion center is a necessary but not sufficient condition to guarantee piezoelectricity.

Piezoelectric effect is extensively used to convert the electric energy into mechanical energy and vice-versa i.e. the piezoelectric substances are used as electromechanical transducers. For instance it is an electric signal that is applied to one end of a quartz rod, the variations in strain generated in the rod in consequence of the effect propagate down the rod constituting what is known as mechanical wave or an acoustic wave. Another important application of piezoelectrics is their use as highly stable oscillators for frequency control [7]. If a quartz crystal is subjected to an alternating voltage at one of its resonant frequencies the crystals will suffer expansion and contraction alternately in consequence of the effect and thus the oscillations of the crystals will be set up. The frequency of these oscillations depends on the dimensions of the specimen and the elastic constants of the material and is stable. Specially cut quartz discs are generally used for this purpose.

Ferro electricity versus piezoelectricity [8]:


#### *Piezoelectricity and Its Applications DOI: http://dx.doi.org/10.5772/intechopen.96154*

The inverse effect–that these crystals become strained when polarized has also been

. Conversely small strains can produce large electric fields.

no charge distortion hence no polarization.

sary but not sufficient condition to guarantee piezoelectricity.

stable. Specially cut quartz discs are generally used for this purpose.

1. In piezoelectricity the crystal is polarized by the application of an external stress whereas in ferroelectricity the source of polarization is the dipole

2.Both the phenomena occur in noncentrosymmetric crystals, which are 20 in number. Piezoelectricity occurs in all the 20 crystals whereas ferroelectricity

3.All ferroelectrics are therefore piezoelectric but all piezoelectrics are surely not ferroelectric for example Tourmaline is piezoelectric but not ferroelectric at all.

only in 10 namely those which provide a favorable axis of polarity.

4.The piezoelectric coefficient is the ratio of the setup charge to the stress applied to a crystallographic axis. The ferroelectrics have very large

Ferro electricity versus piezoelectricity [8]:

interaction energy itself.

piezoelectric coefficients.

**74**

Piezoelectric strains are very small, and the corresponding electric fields are very large. In Quartz for example a field of 1000 V/cm produces a strain of the order of

To understand the origin of the piezoelectric effect, the distribution of the ionic charges of a crystal about their lattice sites. Normally, the distribution is symmetrical, and the internal electric field is zero. But when the crystal is stressed, the charges are displaced. In a piezoelectric crystal this displacement distorts the original charge distribution in such a way that it is no longer symmetrical - for a quartz crystal. A net polarization results in such crystals and when observing the piezoelectric effect. In other crystals, on the other hand, the distribution of charges maintains its symmetry even after the displacement - for a non piezoelectric crystal. Such crystals exhibit no net polarization and hence no piezoelectric effect [6]. It follows that the piezoelectric effect is related to crystal symmetry. The symmetry element involved is essentially the center of inversion. A crystal can exhibit piezoelectric effect only if its unit cell lacks a center of inversion. This is because when there is no center of inversion, only then the charge distribution is distorted so as to produce polarization. However if the center of inversion is present, there is

It can be proved that of the 32 crystal classes, 21 are non centro symmetrical but since one of these 21 is highly symmetric in other respects, it is piezoelectrically excluded, leaving only 20 piezoelectric classes. However, all crystals belonging to these 20 classes are not observably piezoelectric - in some crystals the piezoelectric effects are too small to be detectable. Thus, the lack of inversion center is a neces-

Piezoelectric effect is extensively used to convert the electric energy into mechanical energy and vice-versa i.e. the piezoelectric substances are used as electromechanical transducers. For instance it is an electric signal that is applied to one end of a quartz rod, the variations in strain generated in the rod in consequence of the effect propagate down the rod constituting what is known as mechanical wave or an acoustic wave. Another important application of piezoelectrics is their use as highly stable oscillators for frequency control [7]. If a quartz crystal is subjected to an alternating voltage at one of its resonant frequencies the crystals will suffer expansion and contraction alternately in consequence of the effect and thus the oscillations of the crystals will be set up. The frequency of these oscillations depends on the dimensions of the specimen and the elastic constants of the material and is

observed.

*Multifunctional Ferroelectric Materials*

10�<sup>7</sup>

The phenomenon of piezoelectricity was discovered just over a hundred years ago by the Curie brothers, Pierre and Jaques. The science of Piezoelectricity has proceeded at an uneven face in these one hundred years. Periods of rapid progress have been followed by periods of slow development and sometimes even by periods of no development (Incidentally, this is characteristic of all branches of science). Every time that piezoelectricity has appeared to be exhausted as a science, the discovery of new piezoelectric effects or new piezoelectric materials initiated a new stage of rapid development and opened up new areas for the application of piezoelectricity. Piezoelectricity is currently enjoying a great resurgence in both Fundamental Research and Technical applications.

Piezoelectricity is one of the basic properties of crystals, ceramics polymers and liquid crystals. There are several ways to describe the piezoelectric effect [9]. Perhaps the most common definition is that a material is piezoelectric if the application of an external mechanical stress causes the development of an internal dielectric displacement. This displacement is manifested as an internal electric polarization or a surface electric charge Because of the way in which the elastic stress and dielectric displacement transform during coordinate axis rotation (**Figure 1**) the piezoelectric constants describing the linear relationship form a third order tensor. A simplified mathematical formulation of the piezoelectric effect is given below. More detail treatments of the piezoelectric effect and Converse effect can be found in texts.

It should be noted that the piezoelectric effect is strongly linked to the Crystal symmetry. All crystals are arranged into 32 point groups. Crystals belonging to the 11 centro symmetric point groups cannot show a piezoelectric effect. Crystals belonging to the non centro symmetric point group O also do not exhibit a piezoelectric effect. Nearly all other non metallic crystals belonging to the remaining 20 point groups exhibit a piezoelectric effect of some magnitude, although some of the effects are very small.

The piezoelectric phenomenon can be described as.

$$\mathbf{P}\_{\rm i} = \mathbf{P}^{0}\mathbf{}\_{\rm i} + \,\_{\rm jk}\mathbf{E}\mathbf{d}\_{\rm ijk}\,\mathbf{T}\_{\rm jk} \tag{12}$$

**Figure 1.** *Piezoelectric effect.*

Where Pi is a component of the polarization vector, P0 <sup>i</sup> the spontaneous polarization and Tjk is the stress tensor component. The coefficient dijk are called the piezoelectric Coefficient and are third rank tensor components.

between electrical and mechanical losses, which can be described by the relaxation of defects which are simultaneously as well electric as elastic dipoles. The heterogeneous system entails a higher degree of complexity, example superposition of uncoupled losses, losses by electric conduction, local field effects orientation distributions and others. Therefore the theoretical treatment is clearer in the two-phase

Piezoelectric ceramics are prepared for fabricating the electromechanical transducers used in the mechanical frequency filters that find application in long-haul Communications systems. These ceramics have to satisfy specifications that can only be met by utilizing all the possibilities offered by the physical effects of the ferroelectric materials. The required positive temperature coefficient of the frequency constant is realized with the aid of elastic anomalies in the region of ferro-

Quartz resonators have been adapted for communications, but in recent years mostly for wrist watches and clocks since the quartz-oscillator circuit which incorporates a piezoelectric quartz crystal resonator has a very stable frequency. Thanks to quartz resonators, time accuracy of wrist watches has been improved rapidly. Quartz resonators for wristwatches and clocks amount to over 60% of total quartz resonators manufactured in Japan. This paper touches upon the characteristics, details of technical advancements, the analysis methods, the manufacturing tech-

Recently electronic wrist watches have spread far and wide, small and beautiful ones with high accuracy and many functions in particular. It owes development of various watch parts including the Integrated circuit. Among them the development of the quartz resonator for wristwatches, which produces the time (frequency)

Elastic vibration of a quartz resonator is transformed into electric Vibration by piezoelectricity because quartz crystal is stable against the ambient temperature, elapsed time and other various environments; frequency of a quartz resonator oscillator is extremely stable. Therefore it has been used in the fields of wireless communications and recently adapted for wrist watches and clocks. It shows the percentage of quartz resonators by fields produced in Japan. As described, quartz resonators for wrist watches and clocks amount to 64.6% of the total number and

All the electrical devices nowadays are just not limited to electrical connection in between them but have this piezoelectricity as a common thing in all applications. Cell phones, diesel fuel injectors, grill igniters, ultrasonic transducers, acoustic guitar pickups, vibration sensors, certain printers, and musical greeting cards etc. utilizes piezoelectricity. The additional development of manmade piezo materials

The applications of piezoelectricity includes the following fields:

• Actuators in Consumer Electronics (Printers, Speakers)

nique and finally the future trend of quartz resonators for wristwatches.

model.

electric phase transitions.

*Piezoelectricity and Its Applications*

*DOI: http://dx.doi.org/10.5772/intechopen.96154*

standard, is especially splendid.

40.4% of the gross sales.

**3. Applications of piezoelectricity**

which includes piezoelectric ceramics.

• Actuators in Industrial Sector

• Sensors in Medical Sector

• Piezoelectric Motors

**77**

Piezoelectric materials that are currently receiving much scientific attention include piezoelectric semiconductors, such as gallium arsenide, which have a wide range of interesting properties [10]. An existing goal with these materials is to integrate the piezo device and the semiconductor components on the same substrate. The last decade has witnessed an explosive expansion in research on surface acoustic waves. Most recently, the research has concentrated on layered systems containing piezoelectrics. Another important application of surface acoustic waves has been the development of miniature high-frequency "bulk structure" filters using Lithium niobate and Lithium tantalate crystals for use in consumer electronic applications.

Research into "bulk structure" surface acoustic wave resonators is currently a very active area. Piezoelectric Polymers, thin films and composites are becoming increasingly important. This is evidenced by a series of recent International conferences devoted to PVF2 and other piezoelectric polymers.

Since piezoelectricity was first discovered the applications of piezoelectric materials have mushroomed. Langevin's work opened the large field of ultrasonics, which now includes detection, nondestructive evaluation, acoustic electricity, acousto optics, and imaging, signal processing, physical acoustics, medical acoustics etc.

Early Works By Cady and Nicolson lead to frequency control including resonators, oscillators and filters [11]. This field initially utilized low frequencies about 100 kHz. As time progressed, higher frequencies were needed and used. The majority of the presently mass produced high frequency piezoelectric filters are based on the Onoe theory of the multimedia resonator. It should be noted that the Onoe theory was inspired by Schockley's theory of energy traps.

Today piezoelectric devices are found in television sets, radios, wristwatches, small computer games, automobiles etc. Many communications and navigation systems used large numbers of very precise piezoelectric resonators for frequency control, generation and selection.

It can be observed that even with quartz the original piezoelectric material, the rate of improvement of the properties of these devices is still in an accelerating phase. For instance, the stability of quartz frequency sources has improved by an order of magnitude every five or six years.

Piezoelectric materials have always played a very significant role in acoustics. In recent times, they have found widespread application as generators, transmitters and detectors of surface acoustic waves.

Of the many biological materials which exhibit piezoelectricity bone belongs to the best investigated ones. Bur has measured various complex piezoelectric constants of bovine bone as a function of frequency, temperature and relative humidity. The presence of water in bone in some piezoelectric constants gives rise to the occurrence of piezoelectric relaxation in others it shifts the relaxation frequency as does the temperature. This piezoelectric relaxation has been qualitatively explained by the two-phase model too. The losses in this case are attributed to a Maxwell Wagner dispersion, which occurs as a result of ionic conduction.

It may appear that the physical mechanism of piezoelectric relaxation by electrical and mechanical interactions between different phases is different from the piezoelectric relaxation as described in the preceding chapters. The basic elements of the piezoelectric relaxation however, are compatible for molecular point defects for two-dimensional defects like domain boundaries and for three-dimensional defects as are the finely dispersed to phase materials. In any case there is a coupling

#### *Piezoelectricity and Its Applications DOI: http://dx.doi.org/10.5772/intechopen.96154*

Where Pi is a component of the polarization vector, P0

*Multifunctional Ferroelectric Materials*

piezoelectric Coefficient and are third rank tensor components.

ences devoted to PVF2 and other piezoelectric polymers.

Onoe theory was inspired by Schockley's theory of energy traps.

Wagner dispersion, which occurs as a result of ionic conduction.

applications.

acoustics etc.

**76**

control, generation and selection.

order of magnitude every five or six years.

and detectors of surface acoustic waves.

zation and Tjk is the stress tensor component. The coefficient dijk are called the

Piezoelectric materials that are currently receiving much scientific attention include piezoelectric semiconductors, such as gallium arsenide, which have a wide range of interesting properties [10]. An existing goal with these materials is to integrate the piezo device and the semiconductor components on the same substrate. The last decade has witnessed an explosive expansion in research on surface acoustic waves. Most recently, the research has concentrated on layered systems containing piezoelectrics. Another important application of surface acoustic waves has been the development of miniature high-frequency "bulk structure" filters using Lithium niobate and Lithium tantalate crystals for use in consumer electronic

Research into "bulk structure" surface acoustic wave resonators is currently a very active area. Piezoelectric Polymers, thin films and composites are becoming increasingly important. This is evidenced by a series of recent International confer-

Since piezoelectricity was first discovered the applications of piezoelectric materials have mushroomed. Langevin's work opened the large field of ultrasonics, which now includes detection, nondestructive evaluation, acoustic electricity, acousto optics, and imaging, signal processing, physical acoustics, medical

Early Works By Cady and Nicolson lead to frequency control including resonators, oscillators and filters [11]. This field initially utilized low frequencies about 100 kHz. As time progressed, higher frequencies were needed and used. The majority of the presently mass produced high frequency piezoelectric filters are based on the Onoe theory of the multimedia resonator. It should be noted that the

Today piezoelectric devices are found in television sets, radios, wristwatches, small computer games, automobiles etc. Many communications and navigation systems used large numbers of very precise piezoelectric resonators for frequency

It can be observed that even with quartz the original piezoelectric material, the rate of improvement of the properties of these devices is still in an accelerating phase. For instance, the stability of quartz frequency sources has improved by an

Piezoelectric materials have always played a very significant role in acoustics. In recent times, they have found widespread application as generators, transmitters

Of the many biological materials which exhibit piezoelectricity bone belongs to the best investigated ones. Bur has measured various complex piezoelectric constants of bovine bone as a function of frequency, temperature and relative humidity. The presence of water in bone in some piezoelectric constants gives rise to the occurrence of piezoelectric relaxation in others it shifts the relaxation frequency as does the temperature. This piezoelectric relaxation has been qualitatively explained by the two-phase model too. The losses in this case are attributed to a Maxwell

It may appear that the physical mechanism of piezoelectric relaxation by electrical and mechanical interactions between different phases is different from the piezoelectric relaxation as described in the preceding chapters. The basic elements of the piezoelectric relaxation however, are compatible for molecular point defects for two-dimensional defects like domain boundaries and for three-dimensional defects as are the finely dispersed to phase materials. In any case there is a coupling

<sup>i</sup> the spontaneous polari-

between electrical and mechanical losses, which can be described by the relaxation of defects which are simultaneously as well electric as elastic dipoles. The heterogeneous system entails a higher degree of complexity, example superposition of uncoupled losses, losses by electric conduction, local field effects orientation distributions and others. Therefore the theoretical treatment is clearer in the two-phase model.

Piezoelectric ceramics are prepared for fabricating the electromechanical transducers used in the mechanical frequency filters that find application in long-haul Communications systems. These ceramics have to satisfy specifications that can only be met by utilizing all the possibilities offered by the physical effects of the ferroelectric materials. The required positive temperature coefficient of the frequency constant is realized with the aid of elastic anomalies in the region of ferroelectric phase transitions.

Quartz resonators have been adapted for communications, but in recent years mostly for wrist watches and clocks since the quartz-oscillator circuit which incorporates a piezoelectric quartz crystal resonator has a very stable frequency. Thanks to quartz resonators, time accuracy of wrist watches has been improved rapidly. Quartz resonators for wristwatches and clocks amount to over 60% of total quartz resonators manufactured in Japan. This paper touches upon the characteristics, details of technical advancements, the analysis methods, the manufacturing technique and finally the future trend of quartz resonators for wristwatches.

Recently electronic wrist watches have spread far and wide, small and beautiful ones with high accuracy and many functions in particular. It owes development of various watch parts including the Integrated circuit. Among them the development of the quartz resonator for wristwatches, which produces the time (frequency) standard, is especially splendid.

Elastic vibration of a quartz resonator is transformed into electric Vibration by piezoelectricity because quartz crystal is stable against the ambient temperature, elapsed time and other various environments; frequency of a quartz resonator oscillator is extremely stable. Therefore it has been used in the fields of wireless communications and recently adapted for wrist watches and clocks. It shows the percentage of quartz resonators by fields produced in Japan. As described, quartz resonators for wrist watches and clocks amount to 64.6% of the total number and 40.4% of the gross sales.
