The role of defects in the physical properties of mechanically activated PbTiO₃ ferroelectrics

In this work a multi-technique characterization was performed for the first time to trace the influence of structural defects on the physical properties of PbTiO₃ ferroelectrics. The structural defects were generated by the mechanical activation in the pressure range of 40-320 MPa, by combining a uniaxial strain with a shear deformation in the Bridgman anvils. The induced defectivity of PbTiO₃ was assessed via calculation of unit cell parameters, estimation of the regions of coherent scattering and analysis of micro-deformations. The Debye characteristic temperature, the static mean-square displacement, the Debye-Waller isotropic factor, the vibrational spectra and dielectric properties of the activated PbTiO₃ ceramics are presented. The high-quality PbTiO₃ ceramics was prepared without modifiers, hence, changing the concentration of structural defects via mechanical activation constitutes a chemically clean method for fine tuning of the dielectric properties of PbTiO₃.