Aging studies of some Pb(Mg1/3Nb2/3)O3 -PbTiO3-(Ba,Sr)TiO3 ceramics

Relaxor ferroelectrics, such as PMN, have a nonconventional domain structure compared to a normal ferroelectric; and thus have aging characteristics that manifest themselves in a somewhat different manner. The focus of this research is to study the effects of aging on PMN based compositions. The samples tested include a number of compositions in the Pb(Mg_1/3Nb_2/3)O₃PbTiO₃ -(Ba,Sr)TiO₃ ternary. The samples were originally fabricated using a columbite precursor mixed oxide method. The electromechanical properties (strain and hysteresis), polarization and weak field permittivity were measured as a function of frequency and temperature for samples aged around ten years. The characteristic "saddle" in the dielectric temperature curves has been investigated for its dependence on time, temperature and frequency. A spectral analysis of these responses shows that the aging effects are apparent in the higher harmonics of the material