The number of ceramic materials with a perovskite type structure is large and of considerable technological importance due to their rich crystal chemistry and structure-property relationships. Applications include multilayer capacitators, piezoelectric transducers, PTC thermistors, electrooptical modulators, optical switches, dielectric resonators, thick film resistors, electronic sensors, electrorestrictive actuators, magnetic bubble memory devices, laser host materials, ferromagnetic materials, refractory electrodes, second harmonic generators, batteries, ceramic electrodes, thermoelectric...