Lead zirconate titanate
Silvery- white odorless solid
7.5-8.0 g · cm -3
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Lead zirconate titanate (PZT ) is a composite material made of lead (Pb ), oxygen (O) and titanium (Ti) or zirconium (Zr ) and belongs to the family of ferroelectric materials.
The lead atoms are arranged in a cubic space structure. Lead zirconate titanate is usually, as the his very similar barium titanate perovskite as before. More oxygen atoms, and a face-centered cubic titanium - zirconium, or " pseudo- body-centered cubic " arranged, meaning that the titanium atom of the above Curie temperature actually occupying the body-centered cubic -described position. At temperatures below the Curie temperature (depending on the titanium content is between about 230 ° C and 500 ° C) the titanium atom migrates slightly out of its central location and the previously electrically neutral grid becomes a dipole. This dipole grating now has piezoelectric properties and is the time (2005) as one of the most cost effective materials for the production of high-performance piezo actuators. PZT is also preferably used as a memory element of a ferroelectric RAM.
PZT as a piezoelectric ceramic
The properties of a PZT material can be modified (doping ) in addition by the incorporation of foreign atoms. Special importance for piezoceramics case has the polarizability at different electric field strengths. By doping arise so-called hard and soft ceramics, which differ in their hysteresis curve. Soft PZT materials are characterized by high remanence, but they show already at a lower field strength, the so-called coercive field, a change in the polarization direction. In hard PZT materials, the reverse is the case: the white between districts, also called domains, are more difficult to change by electric fields. The material is so heavy malleable ( harder ).