BaTiO_3/LaSrMnO_3 (BTO/LSMO) structures with a ferroelectric layer thickness of 10 nm have been formed on r -cut sapphire substrate by means of high-frequency magnetron sputtering. Investigations of the sample structure showed the presence of a crystalline phase, while measurements of electrical properties revealed piezoelectric response of the BTO films. The study of local current–voltage characteristics showed dependence of the sample resistance on the prehistory of voltage application as determined by ferroelectric hysteresis of the BTO layer.

The structural properties of ferroelectric films of barium titanate-stannate on the sapphire substrates and the microwave characteristics of planar capacitors on their base are investigated. It was found that the composition of the gas ambient during the deposition of the film has a significant effect on the crystal structure, the phase composition of the films and their electrical characteristics. A low level of dielectric loss of planar capacitors with high tunability based on films of barium titanate stannate in the frequency range of 2-60 GHz was demonstrated.

The electrical properties of the tunable capacitors based on the barium-strontium titanate films and the films itself were investigated in a wide frequency range. The dielectric losses of ferroelectric films at frequencies up to 30 GHz were estimated based on the parameters of capacitors. The measurements were performed using the set of resonance techniques. Direct measurements of the film properties were carried out at a frequency of 60 GHz using the open resonator technique. The parameters of the capacitors were compared with semiconductor analogs to demonstrate the prospects of thin-film ferroelectric elements application in the millimeter wavelength range.