POINT DEFECT STUDIES ON PEROVSKITE STRUCTURED PIEZOELECTRIC CERAMICS USING POSITRON ANNIHILATION

A systematic investigation of different types of lattice defects in intentionally doped or impurity substituted piezoelectric ceramics was carried out by using positron annihilation.La3+ doped PbTiO3,Sr2+,Cd2+,and La3+ doped Pb (Mg1/3Nb2/3)0.375Ti0.375Zr0.25O3;Ca2+ doped BaTiO3; and Nb5+ doped SrTiO3 were chosen as testing materials.It was found that positrons can be traped by cation vacancies,oxygen vacancies,as well as defects associated with lattice deformations,but with different dynamic specific trapping rates and annihilation characteristics.A new possible method for determining the defect species in perovskite structured piezoelectric ceramics is presented.