Preparation, structural features, elemental composition of and dielectric properties of a two-layer structure based on thin films of multiferroic BiFeO$_3$ and ferroelectric (Sr, Ba)Nb$_2$O$_6$

BiFeO heterostructures were manufactured using intermittent sputtering technology on the surface of a single crystal substrate MgO(001) BiFeO$_3$/(Sr, Ba)Nb$_2$O$_6$. Studies of the structure, thickness profile of the composition, surface morphology and dielectric characteristics of materials have been carried out. It is established that despite the formation of two types of orientation domains ($\pm$ 18.4$^\circ$) in the layer (Sr, Ba)Nb$_2$O$_6$, the upper layer of BiFeO$_3$ is in the ratio of the total parallel orientation with the substrate MgO(001). It is shown that the composition of the films of bismuth ferrite and barium-strontium niobate does not change in film thickness, corresponds to the compositions of the sprayed ceramic targets, no signs of the presence of buffer layers were revealed. The results of the study of dielectric and ferroelectric characteristics of the heterostructure are presented. The reasons for the revealed patterns are discussed.