Electric field-induced bending by polarized surface layers effect in ferroelectric ceramics

Abstract

Electric field-induced bending in ferroelectric ceramics has attracted considerable interest recently, but the mechanisms of this phenomenon are not fully understood. In this work, we show that electric field-induced bending deformation can be observed in (Ba,Sr)TiO3 ceramics with different concentrations of SrTiO3. Experimental results, such as reduction in bending deformation by removing surface layers and increasing ceramic thickness, suggest that this phenomenon can be well explained by the polarized surface layer mechanism, a key mechanism for the flexoelectric response in ferroelectric ceramics. The variation in bending deformation behaviors with ceramic compositions and temperature was further measured, and the results also support the surface layer mechanism. Our results indicate that the magnitude of the applied electric field is also an important factor affecting the bending behavior of the ceramics due to the modification of the polarization state of bulk when the field is higher than the coercive field of the ferroelectric ceramics. Our study provides a deeper understanding of the electric field-induced bending phenomenon in ferroelectric ceramics.