Ordering phenomena and nanoscale functionalities in oxide films with controlled epitaxy
The field of functional thin films has transformed in the past decade. This is due to the development of experimental techniques that allow synthesizing materials with atomic control, which eventually leads to atomically-defined interfaces, showing the way to much improved devices and, in some cases, to totally new device concepts. Here I will focus on the challenges related to the synthesis and characterization of ferroic thin films, particularly of oxide thin films, and the ordering phenomena responsible for their large and tunable electrical, mechanical or magnetic responses, which are directly linked to their ferroelectric, ferroelastic or magnetic nature. I will discuss the role of epitaxy on the atomic structure (strain engineering) but also on the microstructure and properties. I will illustrate this with examples of our own work on ferroelectric/piezoelectric PZT and BaTiO3, multiferroic TbMnO3 and BiFeO3 or our most recent work on the newly discovered (by the Namlab team in Dresden) nano-ferroelectric Hf0.5Zr0.5O2. Finally, I will offer my vision about future directions in the field of (multi)ferroic oxides.