Practical consequences of the extrinsic contributions to the properties of piezoelectric sensors and actuators

Extrinsic contributions to the piezoelectric properties of ferroelectric ceramic sensors and actuators are described. A new formalism which describes contributions of vibrating domain walls to the piezoelectric properties is presented. The formalism is based on the classical Rayleigh law and allows calculations of the piezoelectric coefficients as a function of amplitude and frequency of the driving field. The domain wall contributions to the piezoelectric properties of lead zirconate titanate (PZT), barium titanate (BaTiO/sub 3/) and high temperature bismuth titanate (Bi/sub 4/Ti/sub 3/O/sub 12/) based ceramics are discussed. The effects of microstructural parameters on the piezoelectric properties of ceramics are discussed in terms of domain wall vibrations. It is demonstrated how piezoelectric properties of ceramics may be tailored by manipulating domain wall contributions.