AFM (Atomic Force Microscopy)

A scanning probe technique that maps surfaces at nanometer resolution using a sharp tip interacting with the sample. Important: Excellent for domain imaging in ferroelectrics using PFM mode.

Amorphous Materials

Solids lacking long-range crystalline order, commonly used in thin films and coatings. Important: Often exhibit different dielectric losses versus crystalline counterparts.

Annealing (Thermal Treatment)

Controlled heating/cooling to alter microstructure, relieve stress or crystallize thin films. Important: Critical step for optimizing ferroelectric phase and properties.

Band Gap

Energy difference between valence and conduction bands determining semiconducting/insulating behavior. Important: In ferroelectric semiconductors band gap affects leakage and device operation.

Barium Titanate (BaTiO₃)

A prototypical ferroelectric ceramic with high dielectric constant used in capacitors and actuators. Important: Temperature-dependent phases control its ferroelectricity (Curie temperature).

Band Diagram

Graphical representation of energy levels across materials/interfaces. Important: Useful for understanding ferroelectric semiconductors and heterostructures.

Carbon Nanotubes (CNTs)

Cylindrical carbon nanostructures with high conductivity and mechanical strength, used in composites and sensors. Important: CNTs can enhance mechanical and electrical pathways in nanocomposites.

Coercive Field (Ec)

Electric field magnitude required to switch ferroelectric polarization. Important: A key parameter when designing devices and selecting driving electronics.

Coulomb Blockade

Quantum transport phenomenon where electron flow is suppressed due to electrostatic charging in small conductors or quantum dots. Important: Relevant in nanoscale electronic devices and single-electron transistors.

Crystal Symmetry

Atomic arrangement rules in a crystal; non-centrosymmetric crystals are necessary for piezoelectricity. Important: Only 20 of 21 non-centrosymmetric classes show piezoelectricity.

D33 (Piezoelectric coefficient)

A measure of piezoelectric charge or strain along the poling direction (usually in pC/N). Important: Common metric for actuator/sensor performance.

Dielectric Constant (Permittivity)

Material's ability to store electrical energy in an electric field. Important: High permittivity is useful for capacitors; frequency/temperature dependence matters in applications.

Dielectric Loss (tan δ)

Measure of energy dissipation in a dielectric under alternating fields. Important: Low loss is critical for high-frequency and high-Q applications.

Domain Switching

Reorientation of ferroelectric domains by an external electric field, causing hysteresis. Important: Observed via PFM and P–E loop measurements.

Electroceramics

Ceramic materials engineered for electronic functions (dielectric, ferroelectric, piezoelectric). Important: Includes PZT, BaTiO3 and lead-free alternatives.

Epitaxy

Oriented growth of a crystalline film on a substrate to achieve high-quality thin films. Important: Enables superior ferroelectric thin films with controlled orientation.

Energy Harvesting

Conversion of ambient energy (vibration, heat, light) into electrical energy using piezoelectric/triboelectric devices. Important: Useful for low-power IoT sensors and wearables.

Ferroelectricity

Property of materials with spontaneous polarization that can be reversed by an external electric field. Important: Underlies non-volatile memories, sensors and actuators.

Flexible Electronics

Electronics built on bendable substrates that use flexible conductive and piezoelectric materials for wearables and sensors. Important: PVDF and printed piezo films are common components.

Fatigue (Ferroelectric)

Degradation of switchable polarization after repeated cycling. Important: Material selection and electrode engineering mitigate fatigue.

Graphene

Single-atom-thick carbon sheet with exceptional electrical and mechanical properties used in sensors, electrodes and composites. Important: Can form transparent conductive electrodes for thin-film devices.

Hysteresis Loop (P–E curve)

Polarization vs. electric field curve showing ferroelectric switching, remanent polarization and coercive field. Important: Key measurement for ferroelectric characterization.

Imprint (Ferroelectric)

Preferential internal bias in ferroelectric materials causing asymmetric switching. Important: Impacts device reliability and retention.

Ionic Conductors

Materials where ions, not electrons, carry current—used in batteries and solid electrolytes. Important: Interfacial ionic motion can influence dielectric measurements.

Lead Zirconate Titanate (PZT)

Widely used piezoelectric ceramic combining strong ferroelectric and piezoelectric properties for actuators and sensors. Important: Environmental regulations drive lead-free alternatives research.

Leakage Current

Unwanted DC current through a dielectric that degrades device performance and measurement accuracy. Important: Minimize via good film quality and electrode engineering.

Multiferroics

Materials exhibiting multiple ferroic orders (ferroelectricity + ferromagnetism). Important: Potential for novel memory and spintronic devices.

MEMS (Microelectromechanical Systems)

Miniature devices combining mechanical and electrical elements; piezoelectric films are widely used as actuators/sensors in MEMS. Important: Integration challenges include matching thermal expansion and process compatibility.

Nanocomposites

Materials combining nanoparticles and bulk matrices to enhance mechanical, electrical or dielectric properties. Important: Can improve piezo response or lower dielectric loss.

Nanowires

One-dimensional nanostructures with unique electronic/optical properties used in sensors and nanodevices. Important: Piezoelectric nanowires (ZnO) are used in nanogenerators.

Organic Ferroelectrics

Carbon-based ferroelectrics such as PVDF offering flexibility and low-cost processing. Important: Ideal for flexible sensors and wearable devices.

PUND Measurement

Pulse sequence (Positive-Up-Negative-Down) used to separate switching polarization from non-switching contributions and leakage. Important: Essential for accurate ferroelectric quantification.

PVDF (Polyvinylidene Fluoride)

Ferroelectric polymer used in flexible sensors and energy harvesters due to strong piezo/pyroelectric properties. Important: Processing (poling, stretching) dictates piezo performance.

Perovskite Structure

Crystal structure type (ABO₃) common in many ferroelectrics and oxide materials. Important: Small ionic changes can switch between ferroelectric and non-ferroelectric phases.

PFM (Piezoresponse Force Microscopy)

AFM mode used to image and manipulate ferroelectric domains by measuring electromechanical response. Important: Powerful for nanoscale domain studies and local switching experiments.

Quartz Crystal

SiO₂ crystal with piezoelectric properties historically used for resonators and frequency control. Important: Very stable Q-factor and widely used in timing devices.

Relaxor Ferroelectrics

Materials with diffuse phase transitions and frequency-dependent permittivity peaks used in actuators and transducers. Important: High electrostrictive response and temperature stability in some compositions.

Rietveld Refinement

Method to extract crystal structure information from X-ray/neutron diffraction data by fitting the entire pattern. Important: Key for phase identification in ferroelectric ceramics.

Sputtering (Thin Film Deposition)

Physical vapor deposition technique widely used to deposit ferroelectric and piezoelectric thin films. Important: Process parameters control stoichiometry and film stress.

Sol-gel Processing

Wet-chemistry route to prepare ceramic and oxide thin films or powders via precursor solutions. Important: Low-cost but requires careful annealing to achieve phase purity.

Superlattices

Artificially stacked nanoscale layers used to engineer ferroelectric and electronic properties. Important: Interfacial effects often dominate behavior.

Thin Films

Material layers from nanometers to micrometers thick, central to ferroelectric capacitors and MEMS. Important: Substrate choice and interface control are critical.

Triboelectric Effect

Charge generation via frictional contact; used in triboelectric nanogenerators for energy harvesting. Important: Complementary to piezoelectric harvesters in wearable tech.

Vacuum Annealing

Thermal treatment under vacuum to remove volatiles and control oxygen stoichiometry. Important: Affects leakage and defect chemistry in oxide films.

Zinc Oxide (ZnO)

Piezoelectric semiconductor used in sensors, nanogenerators and optoelectronics. Important: Compatible with low-temperature deposition for flexible substrates.