Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 69: Multiferroic Oxide Thin Films and Heterostructures II (joint session KFM/TT/MA)
TT 69.1: Hauptvortrag
Mittwoch, 14. März 2018, 15:00–15:30, EMH 225
Merging Nonlinear Optics and Multiferroic Heterostructure Design — •Manfred Fiebig — Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland
Despite the large variety of valuable tools that are at our disposals for characterizing oxide thin films, some of their functionalities remain invisible. Buried layers and their ordering and interactions are difficult to access. We show how optical second harmonic generation (SHG) allows us to detect such hidden properties. We show how the real-time dynamics of a domain patterns in multiferroic BiFeO3 is tracked by SHG through a ferromagnetic metallic cover layer, thus identify the magnetoelectric domain coupling nondestructively during the poling process [1]. SHG furthermore resolves the domain-wall architecture in tetragonal ferroelectric thin films. In PbZr0.2Ti0.8O3 films it quantifies the buried distribution of a- and c-domains and reveals that c-domain walls exhibit a mixed Ising-Néel-type transverse rotation of polarization across the wall [2]. Finally, by coupling a laser beam into the deposition chamber, SHG follows the evolution of the spontaneous polarization of complex multiferroic heterostructure in real time and with monolayer sensitivity throughout the entire deposition process. Such in-situ SHG allows us tailor heterostructures with an arbitrary sequence of ordered states which could become the key to whole new class of functional ferroelectric materials [3].
[1] M. Trassin et al., Adv. Mater. 27, 4871 (2015). [2] G. De Lucaet al., M. Trassin, Adv. Mater. 29, 1605145 (2017). [3] G. De Lucaet al., Nature Comm. 8, 1419 (2017)