What are ferroelectric ceramics?
Ferroelectric ceramics is a class of crystalline pyroelectric materials - ie materials that are cooled electrically polarized when cooling below a specific temperature. The critical temperature in this regard is the Curie point, which may be better known as the temperature, above which pheromagnetic materials such as iron will lose magnetism. However, the ferroelectric term does not have a direct connection with iron. In materials that show a ferroelectric effect, the polarity can be turned under the influence of the electrical field of the orientation. Many ceramic materials with this feature can be made by heating powder ingredients to the desired temperature and allowing crystallization how the material cools down. These compounds have a general ABX 3 , Where and is a large cation, B is a much smaller cation and X is anion, usually oxygen. The crystal structure of these materials is that "a" cations form a cubic lattice S, inside each cube, "B" a cation surrounded by six "X" anions. PerovatoThe structures do not have the center of symmetry in that the "B" cation tends to be moved from the center - this is necessary for a ferroelectric effect. Examples of ferroelectric ceramics with this type of crystal structure are the Titanate Barya (Batio 3 ), lead titanate (pbtio 3 ) and potassium niobate (KNBO 3 ).
When the electric field is applied, it changes the "B" position in the crystal grid according to the field orientation and remains in these positions when the field is off. This results in the material to become electrically polarized. However, the position of cations "B" can be changed by applying an electric field with a different orientation. In this way, ferramic ceramics can record information and can therefore be used for computer memory.
One of the most important applications of ferroelectrics is ferroelectric memory with random access (FRAM). It offers a very fast storage and a DecreeData editing, advantageous that stored data is maintained if there is no power source. Ferroelectric ceramics are also very suitable for use in capacitors. Multilayer capacitors consisting of hundreds of thin sheets of Barria titanate with printed electrodes are produced in large quantities and have a wide range of uses, for example for ultrasound imaging and infrared cameras with high sensitivity. Other applications include thin -layer ferroelectric ceramics that can be used in optical wavy pipes and optical memory displays.