Large flexoelectric polarization in ceramic lead magnesium niobate

Flexoelectric coefficient mu (12) is greatly enhanced in the relaxor ferroelectric lead magnesium niobate ceramic. Phenomenological analysis suggests the high dielectric permittivity is inadequate to explain the great enhancement. Temperature dependent measurement reveals a close relation between the flexoelectric polarization and the preexisting polar microregions in this relaxor ferroelectrics. It is proposed that the strain gradient might change the Gibbs free energy of the relaxor system and easily reorient the already existing polar microregions, leading to the greatly enhanced flexoelectric effect. (C) 2001 American Institute of Physics.