Electromechanical anisotropy behavior in Pb_0.88Eu_0.08Ti_1−yMn_yO₃ system: Role of 90° domain reversal

An indirect observation of 90° domain reversal under the influence of a poling field process was undertaken by an x-ray diffraction study in the Pb_0.88Eu_0.08Ti_1™y Mn_yO₃ (y = 0, 0.01, 0.02, and 0.03) piezoelectric anisotropic system. The optimum condition k_p → 0 was achieved for y = 0.02 composition. A large percentage of 90° domain rotation was necessary, but not a sufficient condition for the ultrahigh electromechanical anisotropy manifestation. A large microstrain originated by structural defects in unpoled samples seemed to play a crucial role in the attainment of this piezoelectric anisotropy. A breaking in the translational periodicity due to induced vacancy in Pb and O sites by Eu³⁺ and Mn²⁺ substitutions was manifested in the nonuniform variance of the tetragonality (c/a), the large microstrain, and the detriment of crystallinity observed.