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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. Here, it is shown how the dynamic writing of domains in BaTiO3 thin films changes by varying scanning speeds in the range of RH between 2.5% and 60%. The measurements reveal that the critical speed for domain writing, which is defined as the highest speed at which electrical writing of a continuous stripe domain is possible, 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 μ 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.

Ferroelectric Thin Film‐Based Memories In article number 2100650, Gustau Catalan, Neus Domingo, and co‐workers demonstrate that the maximum speed at which ferroelectric thin film‐based memories can be written accelerates with atmospheric humidity – and, conversely, slows down in dry conditions. The domain width as a function of relative humidity follows the behavior of the water adsorption isotherm, revealing the interplay between water layer thickness and screening. Image by Damaso Torres, ICN2.