Effects of structure ordering, structure defects and external conditions on properties of complex ferroelectric perovskites

Structural rearrangements in lead-containing (A′A″) (B′B″)O3 type perovskite compounds are caused by technological treatment, high-energy radiation and ambient conditions. Variation of structure ordering along with modification (substituted or defected solid solutions) may provide promising compositions for applications, e.g., cascade microcryogenic devices (PST solid solutions); efficient piezoelectric materials - here the new (1-x)Pb(Lu1/2Nb1/2)O3-xPbTiO3 system in the morphotropic region. The maximum values of the electromechanical coupling coefficients kp = 0.663, kt = 0.481, k31 = 0.355 were attained in compositions PLuNT 59/41 (Tm = 353 °C) near the morphotropic phase boundary. In P(L)ZT and PLT thin films asymmetry of piezoelectric coefficient d33 hysteresis diminished values of d33 and their frequency dependence were attributed to residual stress at the film-substrate/electrode interfaces and unrelaxed strain characteristic in highly oriented thin films. Neutron irradiation by fluence 1018n/cm2 causes some changes in thin film properties, however, they are less pronounced compared to bulk material of the same composition.