Desired Properties of Piezoelectric Materials

Generally, actual material property requirements depend on the specific material application like sensor, actuator or transducer. Applicability for one case does not automatically mean applicability for another device. Based on the application design not only material form (crystal, ceramics, thin film) but also particular material choice must be done. As an example, following properties ate desired in applications for force, pressure or accelerator sensors  

Low production costs are required generally for arty product. Manufacturing and processing technology is chosen with respect to the marketing needs of the product. Pricing is a cracial point for material and technology choice. 

High piezoelectric sensitivity is governed by the piezoelectric material coefficients r/,A.[CN ]. While piezoelectricity is limited only to the anisotropic materials, piezoelectric coefficients depend not only on the point group symmetry but also on the specific crystal cut orientation. Piezoelectric coefficient responsible for the device performance should be as high as possible. The other piezoelectric coefficients could also contribute to the effect by the imdesirable coupling. Low-syrrunetry materials are not desirable in applications becairse of it. Special requirements for tlte matrix of piezoelectric coefficients come from the sensors where more piezoelectric coefficients are substantial for the device fimctiom 

High isolation resistivity makes possible quasistatic measurements using piezoelectric sensors. Not only the specific resistivity of the piezoelectric material but also the surface quality must be carefully taken into account. Surface conductivity is dependent on the surface treatment Ternperamre dependence of the isolation resistivity is also very important in the piezoelectric element applications. Smface conductivity might be sharply dependent on the temperature, especially at the temperatures where some phase transition occurs. 

Relating to the application needs material research and development takes place. Some of the materials used in the piezoelectric applications in early history are not 

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