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The article focuses on computer simulations of moire patterns in graphene film on a copper substrate. The surface potential simulates the influence of the substrate on the graphene film. The substrate potential is calculated from the Lennard-Jones paired potential. The interaction between carbon atoms is also determined by the Lennard-Jones potential. It is shown that for two-dimensional structures the parameters of the pair potential differ from the three-dimensional analogue. The simulation results in moire structures in the graphene film. We perform calculations for different orientation angles of graphene relative to the crystal lattice Cu(111). The moire superlattice period decreases with increasing angle between the bond directions of the graphene atoms and the main crystal lattice directions of the substrate. The results of the calculations are in good agreement with the experimental data.

The article aims to study the effect of polarized electric current on the magnetization in antiferromagnetic film by computer modeling. Research uses the Ising model, Monte Carlo method, and Metropolis algorithm. The model considers a two-layer film made of a non-magnetic conductor and a conductive antiferromagnetic film. Spin-polarized electric current is supplied through the lower boundary of the nonmagnetic film. The system simulates a sandwich system of ferromagnetic and antiferromagnetic films separated by a non-magnetic spacer. The role of ferromagnetic film is reduced to the polarization of electric current. Simulations have been carried out for different temperatures. The computer simulation examines the dependence of the magnetization in the antiferromagnetic film on the current strength and the polarization of the electron stream. A computer experiment showed the presence of a current threshold for an antiferromagnetic film well below the Neel temperature. The threshold value depends on the temperature and polarization of the electron stream. In the antiferromagnetic phase, there is a maximum magnetization that can be achieved with spin transfer torque. The current threshold and magnetization limit disappear when approaching the Neel temperature.