The complexity of electroceramic materials cannot be covered exhaustively in the present short chapter; instead, only basic information on the various dielectric effects will be provided. Examples of ceramic and single crystal materials, and their properties and applications.
Many oxide ceramic materials display properties that are conducive to important modern technical applications as sensors, actuators, capacitors, thermistors, varistors, solid electrolytes, ionic conductors, superconductors, permanent magnets with soft and hard characteristics, optoelectronic shutters, and many others. Frequently, such ceramics have distorted perovskite or spinel structures that impart ferro - , piezo - or pyroelectric “ smart ” properties. “ Ferroics ” are oxide ceramics with moveable domain walls that can be shifted in response to electrical, magnetic, temperature, and stress field gradients. They include ferrimagnetics (Y3Fe5O12, YIG), ferroelectrics (BaTiO3), superconductors (YBa2Cu3O7-?), piezoelectrics (Pb(Zr,Ti)O3, PZT), PTC thermistors ((Ba,La)TiO3), hard (permanent) ferrimagnetic materials (BaFe12O19 , magnetoplumbite), soft ferromagnetic (transformer) magnets ((Mn,Zn)Fe2O4), nonlinear electro – optics [(Pb,La)(Zr,Ti)O3; PLZT], electrostrictive ceramics [(Pb(Mg,Nb)O3; PMN], and many others.
In contrast to polycrystalline ceramic materials with ferroic properties, there exist nonferroic single crystal piezoelectrics such as ? - quartz or materials with a calcium gallium germanate ( CGG ) structure, as well as single crystal pyroelectrics with perovskite structure such as lithium tantalate (LiTaO3).
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