In this work, the influence of the concentration of manganese ions in BST films on the capacitance-voltage characteristics (CV characteristics, I–V characteristics, tgδ) of the Cu-Cr/BST/α-Al2O3 and Cu-Cr/BST/GGG structures was studied. To measure the electrophysical characteristics, multiferroic thin-film the samples were made in the form of planar capacitors. Measurements of the electrical properties of the formed planar structures were carried out at a frequency of 1 MHz.