Poling and bending behavior of piezoelectric multilayers based on Ba(Ti,Sn)O3 ceramics

Monolithic ceramic samples with up to four layers of BaTi1−xSnxO3 with different amounts of Sn were prepared. The gradient of the chemical composition has to be transformed into a gradient of piezoelectric properties by a poling process. The hysteresis loops of polarization P(E) and strain S(E) were measured and compared with calculated loops. We assumed that the polarization is constant in all layers. Based on this, the polarization of the multilayer system and the electric field strength in each layer in dependence on the applied voltage can be derived. In a first approximation, the effective strain S3 of the system is determined by the displacement of each layer which depends on the appropriate electric field strength in this layer. The deflection at the end of the bending device (length 15 mm) was measured with an equipment based on a capacitive detector. Monolithic and glued samples with different Sn-contents of the layers were investigated. Maximum values of the bending deflection of about 0.02 μm/V were found.