Active dielectrics physics: Modern view

Active (or adaptive, or controlled, or smart) dielectrics may easily react to changes of temperature, pressure, mechanical stress, electrical and magnetic fields as well as light illumination. Active dielectrics are classified on the pyroelectrics, ferroelectrics, piezoelectrics, electrets, and on posistor and critistor materials, and others. The nature of sensitive properties of active dielectrics is main topic of report. A number of electrical, mechanical and thermal effects of polar crystals are considered, and the reductive model of crystals internal polarity is proposed.