Diameter 25mm Fr: 3Mhz Piezoelectric ceramic sheets
Piezoelectric single crystal refers to the lattice of crystal lattice by the orderly growth of the crystal. This crystal structure is asymmetric and therefore piezoelectric. Such as crystal (quartz crystal), lithium gallium and so on.
Piezoelectric ceramic is a ferroelectric ceramic with piezoelectricity after DC high voltage polarization treatment. The structure of these ferroelectric ceramic grains generally does not have a center of symmetry, there are other axis of polarization with different axes, and their positive and negative charge cell center of gravity do not coincide, Moment - spontaneous polarization (Ps) exists. However, ferroelectric ceramics are polycrystals formed by the aggregation of many fine grains.
These small grains are usually irregularly arranged after the ceramic is sintered. Moreover, the spontaneous polarization between the various grains in the direction of disorder, the total piezoelectric effect will cancel each other out, so the macro often do not exhibit piezoelectric properties. Under the action of external electric field, the spontaneous polarization of ferroelectric ceramics can be turned, and the residual polarization (Pr) remains after the external electric field is removed, as shown in Figure 1.2, where Ec is the coercive field and Psat For saturation polarization (defined).