Ferroelectric thin films and heterostructures VI
Tracks
Venue R9
Wednesday, June 19, 2024 |
13:30 - 14:30 |
R8 |
Overview
Session Chair: Morgan Trassin
13:30 Invited : Takao Shimizu
14:00 Viviann Hole Pedersen
14:15 Ruben Skjelstad Dragland
13:30 Invited : Takao Shimizu
14:00 Viviann Hole Pedersen
14:15 Ruben Skjelstad Dragland
Speaker
Takao Shimizu
National Institute for Materials Science
Film thickness dependency of domain structure in (100)/(001)-oriented epitaxial PbTiO3 films
Abstract
PbTiO₃ is a typical tetragonal ferroelectric material with large anisotropy. Its domain structure has been investigated mainly under tensile strain and film thickness below 100 nm
In this study, we grew (100)/(001)-oriented epitaxial PbTiO₃ films with various film thicknesses on (100) SrTiO₃ and (100) KTaO₃ substrates by metal-organic chemical vapor deposition. Domain structure change with strain and film thickness was systematically investigated by high-resolution XRD and piezo force microscopy. Perfect (001) orientation changed to a mixture of (100)/(001) orientation when the film thickness increased in the case of the films under compressive strain on (100) SrTiO₃substrates. On the other hand, perfect (100) orientation changed to the mixture orientation for the films under tensile strain on (100)KTaO₃ substrates. These changes can be understood by the remained strain and its relaxation with the increase of the film thickness. This wide range of domain structure changes with strain and film thickness is useful for understanding the domain structure relationships between thin films and bulk single crystals.
In this study, we grew (100)/(001)-oriented epitaxial PbTiO₃ films with various film thicknesses on (100) SrTiO₃ and (100) KTaO₃ substrates by metal-organic chemical vapor deposition. Domain structure change with strain and film thickness was systematically investigated by high-resolution XRD and piezo force microscopy. Perfect (001) orientation changed to a mixture of (100)/(001) orientation when the film thickness increased in the case of the films under compressive strain on (100) SrTiO₃substrates. On the other hand, perfect (100) orientation changed to the mixture orientation for the films under tensile strain on (100)KTaO₃ substrates. These changes can be understood by the remained strain and its relaxation with the increase of the film thickness. This wide range of domain structure changes with strain and film thickness is useful for understanding the domain structure relationships between thin films and bulk single crystals.
Viviann Hole Pedersen
NTNU
Texturing and ferroelectric properties of SrxBa1-xNb2O6 thin films prepared by aqueous solution deposition
Abstract
Lead-free ferroelectric SrxBa1-xNb2O6 (SBN) with a tetragonal tungsten bronze structure offers flexible chemistry and tunable properties. Here we report on SBN thin films synthesized by an environmentally friendly aqueous chemical solution deposition (CSD) route on SrTiO3 single crystal substrates. Three compositions, x=0.4, x=0.5, and x=0.6, and two main texture orientations, with the unique polar axis perpendicular or parallel to the substrate surface, were synthesized using different heating rates and substrate terminations. The lattice parameters, giving the strain in the films, and the texture orientation of the films were investigated as a function of composition, calcination temperature, substrate termination, or thickness with X-ray diffraction. The study showed that Sr-terminated substrates favored perpendicular orientation of the polar axis, while Ti-terminated substrates gave parallel orientation of the polar axis. Further, in situ application of electrical field during X-ray diffraction studies revealed a reversible hysteresis of the c-lattice parameter in the SBN structure confirming the piezoelectric behavior of the films.
Ruben Skjelstad Dragland
NTNU
Ferroelectric domains in hexagonal DyMnO3 polycrystals with inhomogeneous grain-size distribution
Abstract
Domain engineering is crucial for tuning the functional properties of ferroelectrics for various applications, ranging from capacitors to future nanoelectronics. Here, we study the domain structure in polycrystalline hexagonal DyMnO3. The system has a non-uniform grain-size distribution, which we attribute to the position of DyMnO3 at the stability edge between the hexagonal P63cm and the orthorhombic Pbnm phase. Piezoresponse force microscopy measurements show the coexistence of multi-scale domains, varying by up to one order of magnitude in size. The observed correlation between non-uniform grain sizes and the emergent domain structure provides new insights into the complex nanoscale domain physics in ferroelectric polycrystals and gives new opportunities for domain engineering in systems with non-uniform microstructure.