相关论文: Local Magnetic Moments in Nanoscale Systems
We use the Kondo lattice model to investigate the possibility of ferromagnetism and half-metallicity in local moment systems. Using the spectral density approach and making use of the fact that the spontaneous magnetization of local moment…
We analyze the criterion for the appearance of magnetic moments in quasicrystals approximants and liquids Al-Mn. In a Hartree-Fock scheme, it is shown that the Stoner criterion (Un_d(E_F) > 1) does not apply to these systems due to the…
A one-dimensional system of masses with nearest-neighbor interactions and periodic boundary conditions is used to study mode decay and ergodicity in nonlinear, disordered systems. The system is given an initial periodic displacement, and…
The finite size and surface roughness effects on the magnetization of NiO nanoparticles is investigated. A large magnetic moment arises for an antiferromagnetic nanoparticle due to these effects. The magnetic moment without the surface…
Local magnetic moments in disordered sytems can be described in terms of annealed magnetic disorder, in addition to the underlying quenched disorder. It is shown that for noninteracting electron systems at zero temperature, the annealed…
The demagnetizing factor N is of both conceptual interest and practical importance. Considering localized magnetic moments on a lattice, we show that for non-ellipsoidal samples, N depends on the spin dimensionality (Ising, XY, or…
In the Kondo effect, a localized magnetic moment is screened by forming a correlated electron system with the surrounding conduction electrons of a non-magnetic host. Spin S=1/2 Kondo systems have been investigated extensively in theory and…
We examine the effect of the magnetic field on the proximity effect in nanostructures, self consistently using the Bogoliubov-deGennes formalism within the two dimensional extended Hubbard model. We calculate the local density of states and…
Thermal and magnetic effects in a system consisting of thin layers of coupled Ising spins with $S=1/2$ and $S=1$ are considered. The specific heat and the correlation length display maxima at two different temperatures. It is discussed in…
We develop a local moment approach to static properties of the symmetric Anderson model in the presence of a magnetic field, focussing in particular on the strong coupling Kondo regime. The approach is innately simple and physically…
We demonstrate the quantitative measurement of the magnetization of individual magnetic nanoparticles (MNP) using a magnetic force microscope (MFM). The quantitative measurement is realized by calibration of the MFM signal using an MNP…
Superparamagnetic nanoparticles containing hundreds and thousands of coupled electron spins are on the boundary between classical and quantum behavior, and demonstrate features which are typical for paramagnetic spins and absent in…
With the goal of pushing Spintronic devices towards faster and faster timescales, we demonstrate, using ab-intio time-dependent density functional theory simulations of bulk Heusler compounds subject to ultrashort intense laser pulses, that…
The screening of magnetic moments in metals, the Kondo effect, is found to be quenched with a finite probability in the presence of nonmagnetic disorder. Numerical results for a disordered electron system show that the distribution of Kondo…
Closed shell molecular structures are under normal conditions time-reversal invariant. Experimental evidences point, however, towards that this invariance may be locally violated when the structure is in contact with a particle reservoir.…
We perform a study about effects of an applied magnetic field and a finite chemical potential on the size-dependent phase structure of a first-order transition. These effects are introduced by using methods of quantum fields defined on…
The magnetic relaxation of ferromagnetic powders has been studied for many years, largely due to its importance to recording technologies. However, only recently have experiments been performed that resolve the magnetic state of individual…
We have investigated, by the Monte Carlo simulation, spin systems which represent moments of arrayed magnetic nanoparticles interacting with each other only by the dipole-dipole interaction. In the present paper we aim the understanding of…
We present a relativistic and model-independent method to derive structure-dependent electromagnetic finite-size effects. This is a systematic procedure, particularly well-suited for automatization, which works at arbitrarily high orders in…
Magnetic moments in atomic scale domain walls formed in nanoconstrictions and nanowires are softened which affects dramatically the domain wall resistance. We perform ab initio calculations of the electronic structure and conductance of…