Investigation on switching behaviour of 90° ferroelectric domains in (Pb_0.85Sm_0.10) (Ti_0.98Mn_0.02)O₃ piezoelectric ceramics of ultra-high electromechanical anisotropy by the X-ray diffraction technique

Abstract

An investigation on Sm modified PbTiO₃ ceramics of typical ultra-high electromechanical anisotropy was carried out by means of X-ray diffraction (XRD) technique. By introduction of crystal plane orientation density ρ(hkl), a good description of switching behaviour of 90° ferroelectric domains within the ceramic discs poled at different electric forces has been achieved. The results indicate that 90° domains show a strong spatial orientation preference so that most of the 90° walls are oriented with their normal vectors enclosing an angle 45° with the specimen surface. After poling treatment few changes occurred in the 90° wall distribution but noticeable domain wall shifts occurred. Another noteworthy result is that the thickness electromechanical coupling coefficient K _t develops with poling field almost at the same pace as the orientation density gain Δρ (002) of (002) crystal plane does. The implications of their mutual linkage are outlined.