19 research outputs found
SPIN-TRANSFER INDUCED ULTRAFAST PRECESSIONAL SWITCHING ENHANCED BY INTERFACE ANISOTROPY IN A FERROMAGNETIC NANOPILLAR
Abstract Spin-transfer induced ultrafast precessional switching of magnetization in the Co/Cu/Co nanopillar device is studied. Micromagnetic calculations show that, precessional magnetization switching occurs above a threshold current. The presence of interface uniaxial anisotropy in the Co-thin film free layer, influences heavily the current and energy required to initiate the switching in the device, and the speed of the precessional switching. The threshold current and the precessional switching time are significantly reduced by this effect
Dynamic phase transition properties and hysteretic behavior of a ferrimagnetic core-shell nanoparticle in the presence of a time dependent magnetic field
We have presented dynamic phase transition features and stationary-state
behavior of a ferrimagnetic small nanoparticle system with a core-shell
structure. By means of detailed Monte Carlo simulations, a complete picture of
the phase diagrams and magnetization profiles have been presented and the
conditions for the occurrence of a compensation point in the system
have been investigated. According to N\'{e}el nomenclature, the magnetization
curves of the particle have been found to obey P-type, N-type and Q-type
classification schemes under certain conditions. Much effort has been devoted
to investigation of hysteretic response of the particle and we observed the
existence of triple hysteresis loop behavior which originates from the
existence of a weak ferromagnetic core coupling , as well as a
strong antiferromagnetic interface exchange interaction . Most
of the calculations have been performed for a particle in the presence of
oscillating fields of very high frequencies and high amplitudes in comparison
with exchange interactions which resembles a magnetic system under the
influence of ultrafast switching fields. Particular attention has also been
paid on the influence of the particle size on the thermal and magnetic
properties, as well as magnetic features such as coercivity, remanence and
compensation temperature of the particle. We have found that in the presence of
ultrafast switching fields, the particle may exhibit a dynamic phase transition
from paramagnetic to a dynamically ordered phase with increasing ferromagnetic
shell thickness.Comment: 12 pages, 12 figure
Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling
The impact of orange peel coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the switching dynamics of magnetization of the free layer governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The value of the critical current required to initiate the magnetization switching is calculated analytically by solving the LLGS equation and verified the same through numerical analysis. Results of numerical simulation of the LLGS equation using Runge-Kutta fourth order procedure shows that the presence of orange peel coupling between the spacer and the ferromagnetic layers reduces the switching time of the nanopillar device from 67 ps to 48 ps for an applied current density of 4 × 1012Am−2. Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 1012Am−2 to 1.39 × 1012Am−2