Thickness dependence of dielectric and piezoelectric properties from the surface layer effect of BaTiO3-based ceramics

ABSTRACT Nanoscale ferroelectric materials often exhibit a scaling effect of dielectric and piezoelectric properties with thickness. In this work, we demonstrate that a similar scaling effect can also be observed in BaTiO3 and Ba0.83Sr0.17TiO3 ceramics with a sub-millimeter thickness, as manifested by a reduction of weak-field dielectric constant near the Curie temperature, an increase of the coercive field, and a reduction of piezoelectric response with a reduction of sample thickness, especially for the ceramic with a thickness below 0.5 mm. We propose that the scaling effect could be explained by the presence of surface layers with a stabilized ferroelectric phase and a higher coercive field on ferroelectric ceramics. Because the thickness of the surface layers is typically ∼ 10 μm, our results indicate the surface effect may not be negligible when the dimensions of the ferroelectric materials are in millimeter or sub-millimeter scale. This study is important for the understanding of the scaling effect observed in ferroelectric ceramics.