In the article, computer simulation on the behavior of a ferromagnetic thin film on a non-magnetic substrate by computer simulation is performed. The substrate is described by the two-dimensional Frenkel–Kontorova potential. The Ising model is used to describe the magnetic properties of a two-dimensional ferromagnetic film. The Wolf cluster algorithm is used to model the magnetic behavior of the film. A square lattice is considered for an unperturbed ferromagnetic film. Computer simulations show that mismatch of film and substrate periods results in film splitting into regions with different atomic structures. Magnetic properties for the obtained structure have been investigated. The hysteresis loop is calculated using the Metropolis algorithm. Deformations of the substrate lead to a decrease in the phase transition temperature. The Curie temperature decreases both when the substrate is compressed and when stretched. The change in phase transition temperature depends on the decreasing rate of exchange interaction with distance and the amplitude of interaction with the substrate. When the substrate is compressed, an increase in the amplitude of the interaction between the film and the substrate results in an increase in the phase transition temperature. The opposite effect occurs when the substrate is stretched. The hysteresis loop changes its shape and parameters when the substrate is deformed. Compression and stretching of the substrate results in a decrease in coercive force. The reduction in coercive force when compressing the substrate is greater than when stretching. The magnetization of the film is reduced by deformations at a fixed temperature.
In the article computer simulation of ground state for two-dimensional film on the substrate is performed. The influence of the substrate is modeled using a periodic potential. The potential contains a parameter defining the width of the maxima and minima. The film has a simple square crystal lattice. The substrate potential structure models a square lattice. We consider the case of different film coating ratio ratios. The lattice and substrate periods are also different. If the coating coefficient is different from one, mechanical stresses are present in the film. The case with one fixed edge for the film and periodic boundary conditions was investigated. The film atoms do not form a square lattice in this case. The displacements of atoms are periodic. The period depends on the coating factor. A superlattice is present in such film.
The formation of the substrate surface potential based on the Lennard-Jones two-particle potential is investigated in this paper. A simple atom’s square lattice on the substrate surface is considered. The periodic potential of the substrate atoms is decomposed into a Fourier series. The amplitude ratio for different frequencies has been examined numerically. The substrate potential is approximated with high accuracy by the Frenkel–Kontorova potential at most parameter values. There is a field of parameters in which the term plays a significant role, with a period half as long as the period of the substrate atoms. The ground state of the monoatomic film is modeled on the substrate potential. The film may be in both crystalline and amorphous phases. The transition to the amorphous phase is associated with a change in the landscape of the substrate potential. There are introduced order parameters for structural phase transition in the thin film. When changing the parameters of the substrate, the order parameter experiences a jump when changing the phase of the film.
We investigate the magnetic phase transition in a thin film with an antidote lattice by computer simulation. A lattice of non-magnetic antidotes is present in a thin film of several atomic layers. The antidotes form a rectangular lattice. We are looking at two forms of antidotes. The Ising model and Wolf’ cluster algorithm simulate the system’s magnetic behavior. Antidotes act on additional surfaces of the system. This results in a change in the Curie temperature of the system. Dependence of phase transition temperature on holes size and shape is obtained. The phase transition temperature depends on the size of the hole by logarithmic law. The Curie temperature for triangular holes is lower than for square holes. We investigated the magnetization of a thin film with an antidote lattice and constructed a hysteresis loop. The hysteresis loop expands as the hole size decreases. Coercive force depends on the size and shape of the holes. Coercive force varies by nonlinear law.
2D films deformations under action of ferroelectric substrate by computer modeling method are performed in article. The film has a square lattice. We use harmonic law for the energy of interatomic interaction. The substrate effect on the film is simulated by the 2D Frenkel-Kontorova potential. The orientation of the film and the substrate do not match. Different cases for periods of film and substrate are considered. The Monte Carlo method is used for computer modeling. If the period of the film and the substrate coincide, the film atoms are placed at the minimum points of the substrate. The film on the substrate has a square crystal lattice. If the period of the substrate is less than the period of the film, the continuous film is converted into a film 2D nanoparticles. The substrate potential amplitude affects the filling of the space between particles. If the period of the substrate is longer than the period of the film, a superstructure in the form of a periodic lattice with an increased particle concentration is formed in the film. The distribution of atoms in the superstructure is determined by the substrate potential amplitude of the substrate potential.
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