Determination of the dominant factor affecting the change of the phase transition point in thin ferroelectric films

The study was supported by the Russian Foundation For Basic Research, Project № 19-32-50032

Computer modeling of shear strain in the polymer brushes

R.A.G. acknowledge the financial support by the Russian Science Foundation under grant “Methods of microstructural nonlinear analysis, wave dynamics and mechanics of composites for research and design of modern metamaterials and elements of structures made on its base” (No 15-19- 10008)

Computer simulation of the structural phase transitions in thin ferroelectric films

The influence of free surface and depolarizing field on structural phase transitions in thin ferroelectric films from an ordered state to a disordered one is investigated. The dependences of the order parameter on the distance from the free film surface are calculated. It is shown that with the presence of the depolarizing field and in its absence, the effective thickness of the surface layer depends on the temperature. Nearby the phase transition point, the thickness increases indefinitely. Calculations considering depolarizing field showed that the phase transition points for the bulk ferroelectrics and the film under given boundary conditions coincide. Also shown that in the absence of depolarizing field with mixed boundary conditions, the film thickness does not affect the order parameter, and in presence of the field, this influence is observed

Simulation of the surface structure of ferroelectric thin films

Metropolis and Wang-Landau algorithms are described and illustrated on the base two-dimensional Ising model. The influence of the ferroelectric film thickness and the depolarizing field on the spontaneous polarization and the order parameter of the film has been investigated by means of the Monte-Carlo method. Dependences of the polarization of the thin film on the temperature are calculated at different values of its thickness and the potential well depth of the Lennard-Jones potential. To investigate the geometrical and optical properties of textured coatings the anisotropic three-dimensional model based on the fractal plurality of Julia is used. The developed method allows to determine the values of the model parameters for a number of coating samples of steel sheet obtained under different conditions of their formation. The fractal dimension of the objects obtained on the base of this model is determined