  Flexoelectricity (coupling between polarization and strain gradients) is a
property of all dielectric materials that has been theoretically known for
decades, but it is only relatively recently that it has begun to attract
experimental attention. As a consequence, there are still entire families of
materials whose flexoelectric performance is unknown. This is the case, for
example, of antiferroelectrics: materials with an antipolar but switchable
arrangement of dipoles. And yet, these materials could be flexoelectrically
relevant because it has been hypothesised that the origin of their
antiferroelectricity might be flexoelectric. In this work, we have measured the
flexoelectricity of two different antiferroelectrics (PbZrO3 and AgNbO3) as a
function of temperature, up to and beyond their Curie temperature. Neither
flexoelectricity nor the flexocoupling coefficients are anomalously high, but
the flexocoupling shows a sharp peak at the antiferroelectric phase transition.

Materials Science