Lead zirconate titanate (PZT) diagrams

Case contributed by David McGrath

Lead zirconate titanate (PZT) is an inorganic, ceramic, piezoelectric, crystal used in ultrasound transducers. The chemical formula of PZT is Pb[Zr(x), Ti(1-x)]O3, e.g. PbZr(0..52)Ti(0.48) O3. Each individual PZT lattice cell has piezoelectric potential due to the dipole created by the asymmetry of the position of its atoms. Newly-formed PZT crystals are a mixture of rhombohedral and tetragonal lattice cells due to the random orientation of their dipoles. Zr atoms tend to form rhombohedral cells and Ti atoms tend to form tetragonal cells. Before PZT can be used in ultrasound transducers it must be poled, in a process using heat and an electric field, to align the atom dipoles. 

Image 1 (left image): a single PZT cell with a tetragonal shape and dipole

Image 2: when first formed, PZT crystals have random dipole positions that cancel out the overall piezoelectric effect. Atoms: Pb - grey, O - blue, Ti - green, Zr - cream

Image 3: at the Curie temperature of PZT and above it, the lattice and atoms morph into symmetrically cubic cells with central Zr and Ti atoms and no piezoelectric effect

Image 4: the temperature is dropped below the Curie point and an electric field morphs the lattice cells into a tetragonal pattern with a piezoelectric potential

Case Discussion

Author: David McGrath

Illustrations and Animation by: David McGrath

Original video file: https://www.youtube.com/watch?v=Gp-P8D1i4Ps

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Case information

rID: 46897
Published: 24th Jul 2016
Last edited: 14th Apr 2019
Inclusion in quiz mode: Excluded

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