Auxetic behavior under electrical loads in an induced ferroelectric phase

Abstract

The longitudinal and transverse strains were measured as a function of applied electric fields in a bulk ceramic sample of Pb(0.99)Nb(0.02)[(Zr(0.57)Sn(0.43))(0.94)Ti(0.06)](0.98)O(3) at room temperature. Instead of a transverse contraction, a transverse expansion was observed in the electric-field-induced ferroelectric phase after the antiferroelectric-to-ferroelectric phase transition. Therefore, an auxetic behavior was established in monolithic ferroelectric polycrystalline ceramics under electrical loads. The behavior is characterized by a negative strain ratio that is analogous to the Poisson's ratio. The transverse expansion leads to a large hydrostatic piezoelectric coefficient d(h), which suggests new applications of antiferroelectric ceramics in piezoelectric devices.