Micromagnetic simulation of spin transfer torque switching combined with precessional motion from a hard axis magnetic field

2006 ◽  
Vol 89 (25) ◽  
pp. 252509 ◽  
Author(s):  
K. Ito ◽  
T. Devolder ◽  
C. Chappert ◽  
M. J. Carey ◽  
J. A. Katine
Keyword(s):  
Magnetic Field ◽  
Spin Transfer Torque ◽  
Micromagnetic Simulation ◽  
Spin Transfer ◽  
Hard Axis ◽  
Precessional Motion

Micromagnetic simulation on effect of oersted field and hard axis field in spin transfer torque switching

2007 ◽  
Vol 40 (5) ◽  
pp. 1261-1267 ◽  
Author(s):  
K Ito ◽  
T Devolder ◽  
C Chappert ◽  
M J Carey ◽  
J A Katine
Keyword(s):  
Spin Transfer Torque ◽  
Micromagnetic Simulation ◽  
Spin Transfer ◽  
Hard Axis

Field Dependence of Switching Currents in an Exchange Biased Spin Valve

2007 ◽  
Vol 7 (1) ◽  
pp. 344-349
Author(s):  
Hoang Yen Thi Nguyen ◽  
Sung-Jung Joo ◽  
Kuyoul Jung ◽  
Kyung-Ho Shin
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Spin Valve ◽  
Spin Transfer Torque ◽  
Information Storage ◽  
Spin Transfer ◽  
Field Range ◽  
Higher Spin ◽  
Thermal Magnetization ◽  
Negative Field

Current induced magnetic reversal due to spin transfer torque is a promising candidate in advanced information storage technology. It has been intensively studied. This work reports the field-dependence of switching-currents for current induced magnetization switching in a uncoupled nano-sized cobalt-based spin valve of exchange biased type. The dependency is investigated in hysteretic regime at room temperature, in comparison with that of a trilayer simple spin valve. In the simple spin valve, the switching currents behave to the positive and the negative applied magnetic field symmetrically. In the exchange biased type, in contrast, the switching currents respond to the negative field in a quite unusual and different manner than to the positive field. A negative magnetic field then can shift the switching-currents into either negative or positive current range, dependently on whether a parallel or an antiparallel state of the spin valve was produced by that field. This different character of switching currents in the negative field range can be explained by the effect of the exchange bias pinning field on the spin-polarizer (the fixed Co layer) of the exchange biased spin valve. That unidirectional pinning filed could suppress the thermal magnetization fluctuation in the spin-polarizer, leading to a higher spin polarization of the current, and hence a lower switching current density than in the simple spin valve.

scholarly journals Shaped angular dependence of the spin-transfer torque and microwave generation without magnetic field

2007 ◽  
Vol 3 (7) ◽  
pp. 492-497 ◽  
Author(s):  
O. Boulle ◽  
V. Cros ◽  
J. Grollier ◽  
L. G. Pereira ◽  
C. Deranlot ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Angular Dependence ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Microwave Generation

Tuning Resonance Frequency of Spin Wave Localized in an Isolated Skyrmion by Magnetoelectric Couplings

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950009 ◽  
Author(s):  
Rongzhi Zhao ◽  
Wenchao Chen ◽  
Chenglong Hu ◽  
Luyang Chen ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Resonant Frequency ◽  
Total Energy ◽  
Average Energy ◽  
Spin Transfer Torque ◽  
Spin Transfer ◽  
Integer Multiple ◽  
External Perturbations ◽  
Out Of Plane ◽  
Oscillation Frequencies

Understanding the dynamic behavior of an isolated skyrmion with external perturbations has been obstructed due to the difficulty in experimentally observing such an instantaneous phenomenon within picoseconds. Herein, we theoretically investigated the spin-transfer-torque-induced dynamics of an isolated skyrmion excited by external nanosecond-pulse perturbations. It is found that a redshift of the resonant frequency appears under a pulse polarized current with [Formula: see text][Formula: see text]A/m2 and [Formula: see text][Formula: see text]GHz, while a blueshift is presented under a combined perturbation of the pulse polarized current and an out-of-plane ac magnetic field. The physic origins of the redshift and the blueshift are ascribed to the increased average energy of system from [Formula: see text][Formula: see text]J to [Formula: see text][Formula: see text]J and integer multiple (twofold and fourfold) oscillation frequencies of total energy, respectively. The present study could thus provide an insight to the micromagnetic dynamics of skyrmion under the magnetoelectric couplings.

scholarly journals Micromagnetic Simulation of Spin Transfer Torque Magnetization Precession Phase Diagram in a Spin-Valve Nanopillar under External Magnetic Fields

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
H. B. Huang ◽  
X. Q. Ma ◽  
Z. H. Liu ◽  
X. M. Shi ◽  
T. Yue ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Magnetic Fields ◽  
Dynamic Balance ◽  
Spin Valve ◽  
Spin Transfer Torque ◽  
Micromagnetic Simulation ◽  
Spin Transfer ◽  
Magnetization Distribution ◽  
Magnetization Precession ◽  
Evolution Behavior

We investigated spin transfer torque magnetization precession in a nanoscale pillar spin-valve under external magnetic fields using micromagnetic simulation. The phase diagram of the magnetization precession is calculated and categorized into four states according to their characteristics. Of the four states, the precessional state has two different modes: steady precession mode and substeady precession mode. The different modes originate from the dynamic balance between the spin transfer torque and the Gilbert damping torque. Furthermore, we reported the behavior of the temporal evolutions of magnetization components in steady precession mode at the condition of the applied magnetic field using the orbit projection method and explaining perfectly the magnetization components evolution behavior. In addition, a result of a nonuniform magnetization distribution is observed in the free layer due to the excitation of non-uniform mode.

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