SKM 2021 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 1: Focus Session I: Ferroics - Domains and Domain Walls

KFM 1.1: Hauptvortrag

Dienstag, 28. September 2021, 10:00–10:30, H2

Effect of humidity on the ferroelectric domain wall dynamics in BaTiO3 thin films — Irena Spasojevic¹, Albert Verdaguer², Gustau Catalan¹, and •Neus Domingo¹ — ¹Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain — ²Institut de Ciència de Materials de Barcelona (ICMAB), CSIC, Campus UAB, Bellaterra, 08193 Barcelona, Spain

The switching dynamics of ferroelectric polarization under electric fields depends on the availability of screening charges in order to stabilize the switched polarization. In ferroelectrics thin films with exposed surfaces investigated by piezoresponse force microscopy (PFM), the main source of external screening charges is the atmosphere and the water neck, and therefore relative humidity (RH) plays a major role. In this context dynamic writing of linear domains in BaTiO3 thin films changes by varying scanning speeds in the range of RH between 2.5% and 60% reveal that the critical speed for domain writing increases non-monotonically with RH. Additionally, the width of line domains shows a power law dependence on the writing speed, with a growth rate coefficient decreasing with RH. The size of the written domains at a constant speed as well as the creep-factor describing the domain wall kinetics follow the behavior of water adsorption represented by the adsorption isotherm, indicating that the screening mechanism dominating the switching dynamics is the thickness and the structure of adsorbed water structure and its associated dielectric constant and ionic mobility.