Lead zirconate titanate, also called lead zirconium titanate and commonly abbreviated as PZT, is an

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is a ceramic

perovskite Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula ). Its name is also applied to the class of compounds which have the same type of crystal structure as , known as the perovskite (stru ...

material that shows a marked

piezoelectric effect Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied stress (mechanics), mechanical s ...

, meaning that the compound changes shape when an electric field is applied. It is used in a number of practical applications such as

ultrasonic transducer Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert signal (electrical engineering), ...

s and piezoelectric resonators. It is a white to off-white solid. Lead zirconium titanate was first developed around 1952 at the

Tokyo Institute of Technology The Tokyo Institute of Technology () was a public university in Meguro, Tokyo, Japan. It merged with Tokyo Medical and Dental University to form the Institute of Science Tokyo on 1 October 2024. The Tokyo Institute of Technology was a De ...

. Compared to

barium titanate Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. It is the barium salt of metatitanic acid. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a Ferroelectricity, ferroe ...

, a previously discovered metallic-oxide-based

piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied stress (mechanics), mechanical s ...

material, lead zirconium titanate exhibits greater sensitivity and has a higher operating temperature. Piezoelectric ceramics are chosen for applications because of their physical strength, chemical inertness and their relatively low manufacturing cost. PZT ceramic is the most commonly used piezoelectric ceramic because it has an even greater sensitivity and higher operating temperature than other piezoceramics.

Electroceramic properties

Being piezoelectric, lead zirconate titanate develops a

voltage Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...

(or potential difference) across two of its faces when compressed (useful for sensor applications), and physically changes shape when an external electric field is applied (useful for actuator applications). The

relative permittivity The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the vacuum permittivity, electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric co ...

of lead zirconate titanate can range from 300 to 20000, depending upon orientation and doping. Being pyroelectric, this material develops a voltage difference across two of its faces under changing temperature conditions; consequently, lead zirconate titanate can be used as a heat sensor. Lead zirconate titanate is also

ferroelectric In physics and materials science, ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoel ...

, which means that it has a spontaneous electric polarization ( electric dipole) that can be reversed in the presence of an electric field. The material features an extremely large

at the morphotropic phase boundary (MPB) near ''x'' = 0.52. Some formulations are ohmic until at least (), after which current grows exponentially with field strength before reaching avalanche breakdown; but lead zirconate titanate exhibits time-dependent dielectric breakdown — breakdown may occur under constant-voltage stress after minutes or hours, depending on voltage and temperature, so its dielectric strength depends on the time scale over which it is measured. Other formulations have dielectric strengths measured in the range.

Uses

Lead zirconate titanate-based materials are components of

ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...

capacitor In electrical engineering, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. The capacitor was originally known as the condenser, a term st ...

s and STM/ AFM actuators (tubes). Lead zirconate titanate is used to make

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

transducer A transducer is a device that Energy transformation, converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, M ...

s and other

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

s and

actuator An actuator is a machine element, component of a machine that produces force, torque, or Displacement (geometry), displacement, when an electrical, Pneumatics, pneumatic or Hydraulic fluid, hydraulic input is supplied to it in a system (called an ...

s, as well as high-value ceramic

s and FRAM chips. Lead zirconate titanate is also used in the manufacture of ceramic resonators for reference timing in electronic circuitry. Anti-flash goggles featuring PLZT protect aircrew from burns and blindness in case of a nuclear explosion. The PLZT lenses could turn opaque in less than 150 microseconds. Commercially, it is usually not used in its pure form, rather it is doped with either acceptors, which create oxygen (anion) vacancies, or donors, which create metal (cation) vacancies and facilitate domain wall motion in the material. In general, acceptor doping creates ''hard'' lead zirconate titanate, while donor doping creates ''soft'' lead zirconate titanate. Hard and soft lead zirconate titanate generally differ in their piezoelectric constants. Piezoelectric constants are proportional to the polarization or to the electrical field generated per unit of mechanical stress, or alternatively is the mechanical strain produced by per unit of electric field applied. In general, ''soft'' lead zirconate titanate has a higher piezoelectric constant, but larger losses in the material due to

internal friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding (motion), sliding against each other. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete lis ...

. In ''hard'' lead zirconate titanate, domain wall motion is pinned by the impurities, thereby lowering the losses in the material, but at the expense of a reduced piezoelectric constant.

Varieties

One of the commonly studied chemical composition is . The increased piezoelectric response and poling efficiency near to ''x'' = 0.52 is due to the increased number of allowable domain states at the MPB. At this boundary, the 6 possible domain states from the tetragonal phase ⟨100⟩ and the 8 possible domain states from the rhombohedral phase ⟨111⟩ are equally favorable energetically, thereby allowing a maximum 14 possible domain states. Like structurally similar lead scandium tantalate and barium strontium titanate, lead zirconate titanate can be used for manufacture of uncooled

staring array A staring array, also known as staring-plane array or focal-plane array (FPA), is an image sensor consisting of an array (typically rectangular) of light-sensing pixels at the focal plane of a lens. FPAs are used most commonly for imaging purpo ...

infrared imaging sensors for

thermographic camera Infrared thermography (IRT), thermal video or thermal imaging, is a process where a Thermographic camera, thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are exa ...

s. Both

thin film A thin film is a layer of materials ranging from fractions of a nanometer ( monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many ...

(usually obtained by

chemical vapor deposition Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high-quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (electro ...

) and bulk structures are used. The formula of the material used usually approaches (called lead zirconate titanate 30/70). Its properties may be modified by doping it with lanthanum, resulting in lanthanum-doped lead zirconium titanate (lead zirconate titanate, also called lead lanthanum zirconium titanate), with formula (lead zirconate titanate 17/30/70).

References

External links

zirconate titanate-5A Lead zirconium titanate Material properties
{{Zirconium compounds Ceramic materials Piezoelectric materials Lead(II) compounds Titanates Zirconates Infrared sensor materials Ferroelectric materials Perovskites

Electroceramic properties

Uses

Varieties

See also

References

External links