Various Functional Ceramics

Dielectric materials store electricity by polarization. Under the application of a voltage, positive and negative electric charges are separated, but no DC current flows. Dielectric ceramics are widely used in capacitors because of their high dielectric constant and excellent insulating properties.

Piezoelectric materials convert mechanical energy to electrical energy and vice versa. Murata has conducted extensive research into the piezoelectric characteristics of ceramics and, through the development of piezoelectric ceramic products, has remarkably enhanced the performance of electronic equipment and communications equipment.

Magnetic bodies are materials which generate strong magnetism even in a weak magnetic field, or lines of magnetic force even where there is no magnetic field; in other words materials which have the property of storing magnetic energy. Ferrites are typical of magnetic ceramic materials. They are classified, according to their characteristics, as hard or soft ferrites. Murata has succeeded in exploiting these magnetic properties in EMI suppression filters and to tackle the problems of noise interference.

Among materials electrically polarized due to crystal structure, pyroelectric materials are such that they become electrically polarized with changes in temperature, the amount of electric charge produced varies according to temperature change. Using such materials, Murata has succeeded in mass producing pyroelectric infrared sensors that are able to detect changes in the temperature of people and objects at a distance. Murata's pyroelectric ceramics find application in contactless switches and temperature sensors, satisfying a wide range of needs in the sensor market.

In terms of their ability to conduct electricity, semiconductors lie half way between insulating materials such as glass, which have high resistance, and conductors such as metals, which have low resistance. At Murata, it was noted that the resistance of semiconductors increases at a certain temperature, preventing the flow of current. This means that such semiconductive materials can act as PTC (positive temperature coefficient) thermistors. Exploiting this property, Murata successfully mass produces positive thermistors.