Related papers: Role of atomic vacancies and second-neighbor antif…
By using Monte Carlo simulation on a ferromagnetic core/antiferromagnetic shell nanoparticle, we investigate in details the exchange bias of the magnetic hysteresis as a function of both core radius and shell thickness, at low temperature.…
We study the nanoscale phase coexistence of ferromagnetic metallic (FMM) and antiferromagnetic insulating (AFI) regions by including the effect of AF superexchange and weak disorder in the double exchange model. We use a new Monte Carlo…
We consider superconductivity nucleation in multiply connected mesoscopic samples such as thin-walled cylinders or rings placed in electrical contact with a ferromagnet. The superconducting critical temperature and order parameter structure…
A two dimensional magnetic particle in the presence of an external magnetic field is studied. Equilibrium thermodynamical properties are derived by evaluating analytically the partition function. When the external field is applied…
The two-dimensional Hubbard model with a bimodal distribution of on-site interactions, P(U_i) = (1-f)\delta(U_i-U) + f\delta(U_i), is studied using a finite temperature quantum Monte Carlo technique and dynamical mean-field theory. We find…
A nucleation picture of magnetization switching in single-domain ferromagnetic nanoparticles with high local anisotropy is discussed. Relevant aspects of nucleation theory are presented, stressing the effects of the particle size on the…
We have investigated the room temperature ferromagnetic order that develops in Al-substituted magnesium oxide, Mg(Al)O, nanoparticles with Al fractions of up to 5 at.%. All samples, including undoped MgO nanoparticles, exhibit room…
We present the results of Monte Carlo simulations of the magnetic properties of a model for a single nanoparticle consisting in a ferromagnetic core surrounded by an antiferromagnetic shell. The simulations of hysteresis loops after cooling…
We present a detailed, quantitative study of the competition between interaction- and disorder-induced effects in electronic systems. For this the Anderson-Hubbard model with diagonal disorder is investigated analytically and by Quantum…
The roles of oxygen vacancies on the electronic and magnetic properties of Ni doped In$_2$O$_3$ have been studied by first-principles calculations based on hybrid functional theory. Our results predict that the Ni-doped In$_2$O$_3$ system…
Exchange couplings are fundamental to our understanding of many physical phenomena in condensed matter physics and material science. Model systems provide a controlled environment to investigate such phenomena, effectively. In this study,…
Most previous investigations have shown that the surface of a ferromagnetic material may have antiferromagnetic tendencies. However, experimentally the opposite effect has been recently observed: ferromagnetism appears in some nano-sized…
We present an atomistic model of a single nanoparticle with core/shell structure that takes into account its lattice strucutre and spherical geometry, and in which the values of microscopic parameters such as anisotropy and exchange…
Density-functional calculations are carried out to investigate incommensurate magnetic structures and ferroelectric polarization in newly discovered multiferroic material MnI$_2$. The exchange interactions among local moments on Mn are…
Because of large spatial separation of the Mn atoms in Heusler alloys the Mn 3d states belonging to different atoms do not overlap considerably. Therefore an indirect exchange interaction between Mn atoms should play a crucial role in the…
We consider the interaction of electromagnetic radiation of arbitrary polarization with multi-level atoms in a self-consistent manner, taking into account both spatial and temporal dependencies of local fields. This is done by numerically…
We present a numerical study of the magnetic structure of nanostructured iron fluoride, using the Monte-Carlo-Metropolis simulated annealing technique and a classical Heisenberg Hamiltonian with a superexchange angle dependence. The…
Magnetic materials are typically described in terms of the Heisenberg model, which provides an accurate account of thermodynamic properties when combined with first principles calculations. This approach is usually based on an energy…
Monte Carlo simulation has been employed to investigate the magnetic properties and phase diagrams of ferrimagnetic mixed-spin (1/2, 1) triangular Ising nanotube with core-shell structure. In particular, the effect of the exchange couplings…
Micromagnetic simulations are used to examine the effects of cubic and axial anisotropy, magnetostatic interactions and temperature on M-H loops for a collection of magnetic dipoles on fcc and sc lattices. We employ a simple model of…