  Substitutions of the zirconium and tin ions along with the indium-niobium and
iron-niobium complexes for titanium in the barium modified NBT solid solutions
impact the formation of phases in the process of the solid state synthesis and
the relative stability of the antiferroelectric and ferroelectric phases. We
showed that the synthesis of solid solutions is a multi-step process during
which a number of intermediate phases (depending on the solid solution
composition and the annealing temperature) are formed. The sintering
temperature to 1000 - 1100 C allows to obtain single phase solid solutions. The
increase of the substituting ion content results in a linear variation in the
lattice unit cell size. At the same time it leads to a change in the relative
stability of the antiferroelectric and ferroelectric phases according to the
variation of the tolerance factor. Substitutions by ions with a radius larger
than the radius of the initial ion leads to a decrease of the
ferroelectric-antiferroelectric phase transition temperature while the smaller
ion substitutions produce the opposite effect.
