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The origin of huge piezoelectric strains in PZT thin films

MSc Thesis Project

Available immediately (March 2019) to ambitious students in Applied Physics.

Project motivation:

Lead zirconate titanate (Pb(Zr1-xTix)O3, PZT) is one of the best performing ferroelectric materials with countless applications. In our projects PZT thin films are applied in the development of biomedical sensors, energy storage devices, inkjet print head actuators, and ‘moving mirrors’ for EUV lithography. In our thin films with columnar microstructure we can achieve huge piezoelectric strains of up to 1 %, much larger than any other known thin films. We have a model that can explain this effect and now we want to experimentally confirm it.

Project goal:

We want to relate macroscopically measured strain to measured crystal lattice deformations due to applied E-field in films with nanometer sized polarization domains, as well as determine the induced change in domain fractions. In this way we want to experimentally confirm the origin of the huge piezoelectric strains in these PZT thin films.


Possible tasks of a MSc student:

  • Measure the orientation and relative amounts of ferroelectric domains using a state of the art microfocus X-ray diffractometer.
  • Perform in-situ measurements with the X-ray beam on single devices while applying local electric fields.
  • Measure ferroelectric device properties such as S-E, P-E, and C-V loops, retention, and fatigue.
  • Interpret the results in terms of the available model, expand this model.
  • If interested, the student can obtain a professional cleanroom training and independently perform photolithography, metal electrode sputtering, and ion etching; grow thin films by pulsed laser deposition (PLD); image and characterize the samples by SEM-EDX.

Successful candidates can become co-author of a peer-reviewed publication.


Contact:

Ir. Yorick Birkhölzer, CR 3215, y.a.birkholzer@utwente.nl

Dr. Evert Houwman, CR 3215, e.p.houwman@utwente.nl

Inorganic Materials Science Group

https://www.utwente.nl/en/tnw/ims/


       

Figures adapted from: Nguyen, Houwman, Rijnders, 2017, Sci. Rep,
“Large piezoelectric strain with ultra-low strain hysteresis in highly c-axis oriented Pb(Zr0.52Ti0.48)O3 films with columnar growth on amorphous glass substrates“, DOI: 10.1038/s41598-017-13425-w