Antiferroelectricity in NaNbO₃ freestanding oxide membranes
Advanced Research Lab, Master Thesis
Get practical experience in the novel scientific field of freestanding oxide membranes for antiferroelectric applications.
Antiferroelectric materials have gained significant attention due to their electric field-induced anti ferroelectric – ferroelectric phase transition, making them promising candidates for applications such as high energy density capacitors and electrocaloric devices. Despite the large number of well-studied ferroelectrics, relatively few anti ferroelectric systems have been explored in depth. Among these, perovskite sodium niobate (NaNbO3) stands out as a promising lead-free alternative to conventional antiferroelectric materials such as PbZrO3.
We have studied how strain affects the structural and electrical properties of NaNbO3 thin films. Compressive and small tensile strains preserve the antiferroelectric structure, whereas larger tensile strains destabilise it. To overcome these substrate-induced constraints, we extend this approach by fabricating freestanding oxide membranes of NaNbO3, using a water-soluble sacrificial layer to release the films. This enables access to the intrinsic behavior of NaNbO3 by releasing the films epitaxial strain.
The focus of your work will be to deposit NaNbO3 films by pulsed laser deposition, including the growth of a bottom electrode and a sacrificial layer for lift-off. Then you will characterise their structural properties to understand the crystal structure and film quality. You will produce freestanding membranes by lift-off process and investigate their electrical properties. This project will advance understanding of free-standing NaNbO3 membranes and their properties.
During your work you will get deep insights into:
- Pulsed laser deposition of thin films
- X-ray diffraction, and electrical characterisation
- Thin-film patterning using photolithography, including work in a cleanroom
- Valuable experience of work with ultra-high vacuum systems
If you are a curious student, who aims to handle state of the art scientific equipment, then get in touch with us.
You can start your thesis as soon as possible.
A combined Advanced Research Lab + Master project is an option.
Kerndaten
