Synthesis of multiferroics BiFe0.5B0.5O3

It is shown that the solid solutions BiFe0.5B0.5O3 (B = Cr, Mn, Sc, Y, [Ni0.5Ti0.5], [Mg0.5Ti0.5], [Ni0.75W0.25], [Mg0.75W0.25], [Mg0.67Nb0.33], [Ni0.67Nb0.33]) with a perovskite structure by the method of solid-state synthesis at atmospheric pressure and with the application of moderate pressures (20 MPa) can hardly be obtained in a pure form (without foreign phases) because of the destabilization of their structures either in terms of the parameters of the strength or the directionality of chemical bonds in them. The use of the method of solid-state synthesis at atmospheric pressure has permitted obtaining only BiFe0.5Mn0.5O3 with a relatively small content of foreign phases, which is explained by the identity of the ionic radii of Fe3+ and Mn3+ and also by the proximity of the parameters of the strength and directionality of the bonds in BiFeO3 and BiMnO3. The application of many-hour isothermal holdings, the synthesis of BiFe0.5Mn0.5O3 by the sol-gel method or in the presence of a small excess of Bi2O3 (5 wt %) have not led to a noticeable decrease in the amount of impurity phases.