The optical and electrical properties of bismuth ferrite thin films obtained by high-frequency magnetron sputtering in an atmosphere of argon and oxygen (80%+20%) has been studied. Investigations of the optical properties have shown that for polycrystalline bismuth ferrite films the optical band gap is ~2.3 eV, which is in the range of given in the literature values. The dependences of the specific electrical conductivity on the magnitude of the electric field has been studied for the synthesized films. It has been established that the electrical conductivity does not depend on the electric field strength up to the value of E=2.1·106 V/m. The experimental results are discussed in terms of the model of charge carrier injection from aluminum electrode into the conduction band of bismuth ferrite. Keywords: electrical conductivity, strong electric fields, optical absorption coefficient, memristor effect.

Optical and electrical properties of cobalt oxide thin films obtained by ion-beam sputtering in argon atmosphere and argon with the addition of oxygen (PAr=1.1·10-5 Torr) has been investigated in the work. Optical properties investigations showed that, for films of cobalt oxide obtained in argon atmosphere, the optical band gap is independent of the film thickness and is 3.24 eV, which is in the range of given in the literature for the CoO phase values. For cobalt oxide films obtained in mixed atmosphere of argon with the addition of oxygen, two direct optical transitions with energies of 1.45 and 2.1 eV were detected. The presence of two direct allowed optical transitions is associated with the variable valence of cobalt in the Co3O4 compound and the presence of two valence states Co2+ and Co3+. The dependences of specific electrical conductivity of the synthesized films on the magnitude of the electric field were studied. It was found that for all investigated samples, the electrical conductivity does not depend on the electric field strength up to the value of E=106 V/m. The nonlinearity of the dependence of specific electrical conductivity of the synthesized films on electric field strength at E>106 V/m is discussed in terms of the hopping conductivity model and the trap ionization model described by the Poole?Frenkel effect. Keywords: oxide semiconductors, optical absorption coefficient, electrical conductivity, strong electric fields.

The topological features of the formation of (Co40Fe40B20)15(LiNbO3)85 composite films deposited by ion-beam method on a metal electrode Cr/Cu/Cr has been investigated. The presence of a dielectric layer between the upper Cr layer and the CoFe-LiNbO3 film with a thickness of dox~ 15 nm has been established. The difference in the size of granules near the amorphous layer and in the volume of the film has been shown. A model of the formation of (Co40Fe40B20)x(LiNbO3)100-x nanocomposite film at the initial stage of growth has been proposed. It has been shown that the formation of α-LiNbO3 layer on the chrome metal film surface is possible with the realization of island and layer-by-layer growth mechanisms for various phases of the composite. Keywords: nanocomposite, growth mechanisms, self-organization, structure.

Influence of oxygen and water vapor in vacuum chamber during the deposition process of (Co40Fe40B20)x(LiNbO3)100-x thin film nanocomposites on electrical properties has been investigated. A significant growth in the electrical resistivity of (Co40Fe40B20)x(LiNbO3)100-x nanocomposites has been established with an increase in reactive gases partial pressure (oxygen and water vapor). It has been found, that the recrystallization temperature of composites deposited in argon atmosphere also increases with metallic phase concentration. While the recrystallization temperature of (Co40Fe40B20)x(LiNbO3)100-x nanocomposites sinthesized in mixed atmosphere of Ar with the reactive gases (oxygen or water vapor) decreases due to increase of the heterogeneous structure oxidation. Keywords: Metal-insulator nanocomposites, electrical resistivity, thermal stability, phase composition, oxygen, water vapor.