Morphotropic phase boundary and pyroelectric properties in Pb(Mg_1/2W_1/2)O₃-PbTiO₃ system

Aiming to clarify the relaxor vs. normal ferroelectricity relation, structual, dielectric and pyroelectric properties of (1-x)Pb(Mg_1/2W_1/2)O₃(PMW)-xPbTiO ₃(PT) solid solution system have been examined as a function of the concentration x. The morphotropic phase boundary between relaxor (pseudocubic) and normal ferroelectric (tetragonal) phases exists at around x = 0.58. The maximum ∼ 15000 (at 100 kHz) of the peak permittivity was observed at x = 0.58. The large spontaneous polarization Ps (= 42 μC/cm²) was obtained at room temperature at x = 0.6. Feasibility of these materials to pyroelectric applications was checked. The effects of poling and dc-biasing field were also examined.