Barium Titanate
Barium titanate is a ceramic material with the chemical formula BaTiO3. It is a ferroelectric material, meaning it exhibits spontaneous electric polarization even in the absence of an external electric field. This property makes barium titanate useful in a variety of applications, including capacitors, transducers, and nonlinear optics.
Barium titanate has a perovskite crystal structure, which consists of a cubic unit cell with titanium ions at the center and barium ions and oxygen ions at the corners. Barium titanate undergoes a phase transition from cubic to tetragonal at around 130°C, and then from tetragonal to orthorhombic at around 85°C. These phase transitions are accompanied by changes in the material's dielectric and piezoelectric properties.
Barium titanate can be synthesized using a variety of techniques, including solid-state reaction, sol-gel synthesis, and hydrothermal synthesis. The synthesis method used can affect the properties of the resulting material.
When barium titanate is used in capacitors, its high dielectric constant allows for the storage of large amounts of charge. In transducers, its piezoelectric properties allow for the conversion of electrical energy into mechanical energy and vice versa. In nonlinear optics, its nonlinear optical properties allow for the manipulation of light.
Overall, barium titanate is a versatile material with many useful properties that make it valuable in a range of applications.