Search

In the present work, the study of the magnetic properties of magnetite thin films by means of the Monte Carlo-Ising model is addressed. We simulate LxLxd magnetite thin films (being d the film thickness and L the transversal linear dimension of the film, both measured in unit cells) with periodic boundary conditions along transversal directions and free boundary conditions along d-direction, perpendicular to the base plane. In our model, both the three-dimensional inverse spinel structure and the interactions scheme involving tetrahedral and octahedral sites have been considered in a realistic way. We study the relaxation process from two different initial configurations and several temperature values. Non-linear relaxation functions of magnetization and energy, and the corresponding integral relaxation times are computed. Additionally, we estimate the critical exponent for magnetization (Β) which is compared to that obtained for bulk magnetite. [ABSTRACT FROM AUTHOR]

Hereby we simulate qualitatively the phenomena of colossal magnetoresistance in mixed valence manganites, To do this the two dimensional Ising model is used, definig a square spin net where each site corresponds to the local spin t2g of the manganese ions in the lattice structure. Random Resistor Network model is considered in the resistivity calculations, thanks to the physical support of this simple model when applied to our particular problem. Resistance and magnetoresistance curves as a function of temperature for several applied fields, as a produced by the simulation, reproduce qualitative features of plots issued by the literature. [ABSTRACT FROM AUTHOR]

We study the switching behavior of magnetic nanoparticles with non magnetic impurities. The model used in our study is a square-lattice nearest-neighbor kinetic Ising ferromagnet with periodic boundary conditions. The dynamics is simulated through random updates using Glauber single-spin-flip Monte Carlo dynamic. We concentrate on two quantities: the lifetime τ, that is, the time it takes to reach magnetization zero, and the probabilities P (t) and P (H) that a magnetic particle has not switched for a fixed system size and field and for a fixed system size and waiting time, respectively. [ABSTRACT FROM AUTHOR]