The effect of surface termination on dielectric nonlinearity in potassium sodium niobate thin films
Year: 2025
Type: article
Abstract: The impact of alkali‐rich and alkali‐depleted surface terminations on dielectric nonlinearity and ferroelectric properties was investigated in sputtered K 0.5 Na 0.5 NbO 3 (KNN) films. For the alkali depleted surface termination, a ∼3 nm thick amorphous interfacial layer was found near the top electrode. The presence of a non‐ferroelectric interfacial layer reduces both the net remanent ( P r ) and maximum polarization ( P max ) while increasing the coercive field ( E c ) in the KNN films. P max decreased from 31.5 to 30.3 µC/cm 2 , likely due to the reduced electric field in the bulk of the film. The influence of the interfacial layer on dielectric properties was evaluated using a capacitor in series model. After removing the effects of the interfacial layer, the Rayleigh coefficients ε init and α increased by 11 and 47%, respectively. The interfacial layer has more impact on irreversible domain wall motion than on reversible contributions to the relative permittivity. It is believed that this occurs because a higher concentration of defects, such as or , associated with the alkali‐depleted interfacial layer generates internal fields that pin domain walls. Alkali depleted surface terminations also produce a higher pseudo‐activation energy for polarization reversal compared to films with alkali rich terminations, with deeper potential wells in the material's energy landscape.
DOI: 10.1111/jace.70084
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
OpenAlex ID: W4412378590