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 mechanical stress. The word piezoelectricity means electricity resulting from pressure and latent heat. It is derived from Ancient Greek πιέζω (piézō) 'to squeeze or press', and ἤλεκτρον (ḗlektron) 'amber'. The German form of the word (Piezoelektricität) was coined in 1881 by the German physicist Wilhelm Gottlieb Hankel; the English word was coined in 1883.
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 piezoelectric and pyroelectric, with the additional property that their natural electrical polarization is reversible. The term is used in analogy to ferromagnetism, in which a material exhibits a permanent magnetic moment. Ferromagnetism was already known when ferroelectricity was discovered in 1920 in Rochelle salt by Joseph Valasek. Thus, the prefix ferro, meaning iron, was used to describe the property despite the fact that most ferroelectric materials do not contain iron. Materials that are both ferroelectric and ferromagnetic are known as multiferroics.
Lead zirconate titanate, also called lead zirconium titanate and commonly abbreviated as PZT, is an inorganic compound with the chemical formula Pb[ZrxTi1−x]O3(0 ≤ x ≤ 1).. It is a ceramic perovskite material that shows a marked piezoelectric effect, meaning that the compound changes shape when an electric field is applied. It is used in a number of practical applications such as ultrasonic transducers and piezoelectric resonators. It is a white to off-white solid.
In electromagnetism, electrostriction is a property of all electrical non-conductors, or dielectrics, that causes them to change their shape under the application of an electric field. It is the dual property to magnetostriction.
A piezoelectric motor or piezo motor is a type of electric motor based on the change in shape of a piezoelectric material when an electric field is applied, as a consequence of the converse piezoelectric effect. An electrical circuit makes acoustic or ultrasonic vibrations in the piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials, which can produce linear or rotary motion depending on their mechanism. Examples of types of piezoelectric motors include inchworm motors, stepper and slip-stick motors as well as ultrasonic motors which can be further categorized into standing wave and travelling wave motors. Piezoelectric motors typically use a cyclic stepping motion, which allows the oscillation of the crystals to produce an arbitrarily large motion, as opposed to most other piezoelectric actuators where the range of motion is limited by the static strain that may be induced in the piezoelectric element.
An ultrasonic motor is a type of piezoelectric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation. Ultrasonic motors differ from other piezoelectric motors in several ways, though both typically use some form of piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials. The most obvious difference is the use of resonance to amplify the vibration of the stator in contact with the rotor in ultrasonic motors. Ultrasonic motors also offer arbitrarily large rotation or sliding distances, while piezoelectric actuators are limited by the static strain that may be induced in the piezoelectric element.
Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric, pyroelectric, and piezoelectric ceramic material that exhibits the photorefractive effect. It is used in capacitors, electromechanical transducers and nonlinear optics.
A thin-film bulk acoustic resonator is a device consisting of a piezoelectric material manufactured by thin film methods between two conductive – typically metallic – electrodes and acoustically isolated from the surrounding medium. The operation is based on the piezoelectricity of the piezolayer between the electrodes.
Walter Guyton Cady was a noted American physicist and electrical engineer. He was a pioneer in piezoelectricity, and in 1921 developed the first quartz crystal oscillator.
Ferroelectric polymers are a group of crystalline polar polymers that are also ferroelectric, meaning that they maintain a permanent electric polarization that can be reversed, or switched, in an external electric field.
Piezoelectric micromachined ultrasonic transducers (PMUT) are MEMS-based piezoelectric ultrasonic transducers. Unlike bulk piezoelectric transducers which use the thickness-mode motion of a plate of piezoelectric ceramic such as PZT or single-crystal PMN-PT, PMUT are based on the flexural motion of a thin membrane coupled with a thin piezoelectric film, such as PVDF.
Gordon Eugene Martin is an American physicist and author in the field of piezoelectric materials for underwater sound transducers. He wrote early computer software automating iterative evaluation of direct computer models through a Jacobian matrix of complex numbers. His software enabled the Navy Electronics Laboratory (NEL) to accelerate design of sonar arrays for tracking Soviet Navy submarines during the Cold War.
A complex oxide is a chemical compound that contains oxygen and at least two other elements. Complex oxide materials are notable for their wide range of magnetic and electronic properties, such as ferromagnetism, ferroelectricity, and high-temperature superconductivity. These properties often come from their strongly correlated electrons in d or f orbitals.
Sodium bismuth titanate or bismuth sodium titanium oxide (NBT or BNT) is a solid inorganic compound of sodium, bismuth, titanium and oxygen with the chemical formula of Na0.5Bi0.5TiO3 or Bi0.5Na0.5TiO3. This compound adopts the perovskite structure.
Alper Erturk is a mechanical engineer and the Woodruff Professor in the George W. Woodruff School of Mechanical Engineering at Georgia Institute of Technology.
Warren Perry Mason was an American electrical engineer and physicist at Bell Labs. A graduate of Columbia University, he had a prolific output, publishing four books and nearly a hundred papers. He was issued over two hundred patents, more than anyone else at Bell Labs. His work included acoustics, filters, crystals and ceramics, materials science, polymer chemistry, ultrasonics, bonding to semiconductors, internal friction, and viscoelasticity.
Susan Trolier-McKinstry is an American materials scientist. She is the Steward S. Flaschen Professor of Materials Science and Engineering and Electrical Engineering at Pennsylvania State University, Director of the W. M. Keck Smart Materials Integration Laboratory, and co-director of the Nanofabrication facility.
Nazanin Bassiri-Gharb is a mechanical engineer in the field of micro and nano engineering and mechanics of materials. She is the Harris Saunders, Jr. Chair and Professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology in Atlanta, Georgia. Bassiri-Gharb leads the Smart Materials, Advanced Research and Technology (SMART) Laboratory at Georgia Tech. Her research seeks to characterize and optimize the optical and electric response of interferometric modulator (IMOD) displays. She also investigates novel materials to improve reliability and processing of IMOD.
Dragan Damjanovic is a Swiss-Bosnian-Herzegovinian materials scientist. From 2008 to 2022, he was a professor of material sciences at EPFL and head of the Group for Ferroelectrics and Functional Oxides.
