相关论文: Ratchet Effect in Magnetization Reversal of Stoner…
Magnetization reversal in magnetic particles is one of the fundamental issues in magnetic data storage. Technological improvements require the understanding of dynamical magnetization reversal processes at nanosecond time scales. New…
Based on the Landau-Lifshitz-Gilbert equation, it can be shown that a circularly-polarized microwave can reverse the magnetization of a Stoner particle through synchronization. In comparison with magnetization reversal induced by a static…
The magnetization reversal of Stoner particles is investigated from the point of view of nonlinear dynamics within the Landau-Lifshitz-Gilbert formulation. The following results are obtained. 1) We clarify that the so-called…
The theoretical limit of the minimal magnetization switching field and the optimal field pulse design for uniaxial Stoner particles are investigated. Two results are obtained. One is the existence of a theoretical limit of the smallest…
The physics of magnetic state change or reversal in single domain magnetic grains (called Stoner particles) is interesting from the fundamental as well as the applied points of view. A change in magnetization can be finely tuned with a…
We examine a charge lattice coupled to a one-dimensional asymmetric potential in the presence of an applied magnetic field, which induces gyrotropic effects in the charge motion. This system could be realized for Wigner crystals in…
Using micromagnetics we demonstrate that the r.f. field produced by a spin valve can be used to reverse the magnetization in a magnetic nanoparticle. The r.f. field is generated using a current that specifically excites a uniform spin wave…
We study magnetization reversal using various r.f. magnetic pulses. We show numerically that switching is possible with simple sinusoidal pulses; however the optimum approach is to use a frequency-swept (chirped) r.f. magnetic pulse, the…
We study the rectified transport of underdamped active noninteracting particles in an asymmetric periodic potential. It is found that the ratchet effect of active noninteracting particles occurs in a single direction (along the easy…
We study the ratchet effect of a damped relativistic particle driven by both asymmetric temporal bi-harmonic and time-periodic piecewise constant forces. This system can be formally solved for any external force, providing the ratchet…
We report results from a computer simulation study on the rotational ratchet effect in systems of magnetic particles interacting via dipolar interactions. The ratchet effect consists of directed rotations of the particles in an oscillating…
Using the complex stereographic variable representation for the macrospin, from a study of the nonlinear dynamics underlying the generalized Landau-Lifshitz(LL) equation with Gilbert damping, we show that the spin-transfer torque is…
Nanomagnetism has recently attracted explosive attention, in particular, because of the enormous potential applications in information industry, e.g. new harddisk technology, race-track memory[1], and logic devices[2]. Recent technological…
Magnetization reversal in a many-spin nanomagnet subjected to an rf magnetic field, on top of a DC magnetic field, is studied by numerically solving the system of coupled (damped) Landau-Lifshitz equations. It is demonstrated that…
A model for single-domain uniaxial ferromagnetic particles with high anisotropy, the Ising model, is studied. Recent experimental observations have been made of the probability that the magnetization has not switched. Here an approach is…
Ratchet effects can appear for particles interacting with an asymmetric potential under ac driving or for a thermal system in which a substrate is periodically flashed. Here, we show that a new type of collective ratchet effect can arise…
Energy-efficient switching of nanoscale magnets requires the application of a time-varying magnetic field characterized by microwave frequency. At finite temperatures, even weak thermal fluctuations create perturbations in the magnetization…
The realization of a directed current for a quantum particle in a flashing asymmetric potential is studied. It is found that a positive current, i.e. in the direction expected for a conventional diffusive ratchet, can be attained at short…
Recently, spin-transfer torque (STT) based magnetization switching has been widely utilized in magnetic resistance-based memories, which have broad applications in microcontroller units and other devices. This study utilizes a macrospin…
We consider a magnetic moment with an easy axis anisotropy energy, switched by an external field applied along this axis. Additional small, time-independent bias field is applied perpendicular to the axis. It is found that the magnet's…