scholarly journals Interplay of Linear and Nonlinear Localization Mechanisms in Spin-Torque Oscillators with a Field Well

2019 ◽  
Vol 64 (10) ◽  
pp. 947 ◽  
Author(s):  
R. V. Verba
Keyword(s):  
Wave Mode ◽  
Spin Torque ◽  
Nonlinear Frequency ◽  
Magnetization Dynamics ◽  
Nonlinear Localization ◽  
Generation Mode ◽  
Spin Wave Mode ◽  
Linear And Nonlinear ◽  
Generation Power ◽  
Nonlinear Frequency Shift

The magnetization dynamics in a spin-torque oscillator with nonuniform profile of a static magnetic field creating a field well is studied by analytic calculations and numerical simulations. It is demonstrated that, in the case of sufficiently deep and narrow field well, the linear localization in the field well dominates the nonlinear self-localization, despite a negative nonlinear frequency shift. A change of the localization mechanism results in a qualitatively different dependence of the generation power on the driving current. For the dominant linear localization, the soft generation mode is realized, while, for the nonlinear self-localization, we observe a hard mode of auto-oscillator excitation. Simultaneously, a difference in the profiles of the excited spin-wave mode can become evident and distinguishable in experiments only in the case of a nonsymmetric field well.

Modulation of interfacial magnetic relaxation timeframes by partially uncoupled exchange bias

2021 ◽  
Author(s):  
Maxim Vladimirovich Bakhmetiev ◽  
Artem Dmitrievich Talantsev ◽  
Alexandr Sadovnikov ◽  
Roman Morgunov
Keyword(s):  
Thin Films ◽  
High Frequency ◽  
Wave Mode ◽  
Second Phase ◽  
Microwave Response ◽  
Magnetization Dynamics ◽  
Static Magnetization ◽  
Magnetization Rotation ◽  
Spin Wave Mode ◽  
Magnetization Behavior

Abstract A set of partially uncoupled NiFe/Cu/IrMn exchange biased thin films with variable thickness of non-magnetic Cu spacer is characterized by ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) techniques applied complementary to reveal time-scale dependent effects of uncoupling between ferromagnetic and antiferromagnetic layers on high-frequency magnetization dynamics. The results correlate with interfacial grain texture variations and static magnetization behavior. Two types of crystalline phases with correlated microwave response are revealed at the ferro-antiferromagnet interface in NiFe/Cu/IrMn thin films. The first phase forms as well-textured NiFe/IrMn grains with NiFe (111)/IrMn (111) interface. The second phase consists of amorphous NiFe/IrMn grains. Intercalation of NiFe/IrMn by Cu clusters results in relaxation of tensile strains at the NiFe/IrMn interface leading to larger size of grains in both the NiFe and IrMn layers. The contributions of well-textured and amorphous grains to the high-frequency magnetization reversal behavior are distinguished by FMR and BLS techniques. Generation of a spin-wave mode is revealed in the well-textured phase, whereas microwave response of the amorphous phase is found to originate from magnetization rotation dominated by a rotatable magnetic anisotropy term. Under fixed FMR frequency, the increase of Cu thickness results in higher magnetization rotation frequencies in the amorphous grains.

SNR Improvement of Envelope Demodulation Using Two Temporal Magnetization Dynamics From Dual-Spin-Torque Oscillator

2018 ◽  
Vol 54 (11) ◽  
pp. 1-4 ◽  
Author(s):  
Y. Nakamura ◽  
M. Nishikawa ◽  
H. Osawa ◽  
Y. Okamoto ◽  
T. Kanao ◽  
...  
Keyword(s):  
Spin Torque ◽  
Magnetization Dynamics ◽  
Snr Improvement

scholarly journals Magnetization Dynamics in a Perpendicular Anisotropy Free Layer under a Spin Torque Effect with Crossed Polarization

2020 ◽  
Vol 25 (1) ◽  
pp. 54
Author(s):  
Nafeesa Rahman ◽  
Rachid Sbiaa
Keyword(s):  
Tunnel Junction ◽  
Magnetic Tunnel Junction ◽  
Film Plane ◽  
Spin Torque ◽  
Spin Angular Momentum ◽  
Perpendicular Anisotropy ◽  
Free Layer ◽  
Magnetization Dynamics ◽  
Magnetization Direction ◽  
Spin Polarized

The transfer of spin angular momentum from a spin polarized current provides an efficient way of reversing the magnetization direction of the free layer of the magnetic tunnel junction (MTJ), and while faster reversal will reduce the switching energy, this in turn will lead to low power consumption. In this work, we propose a design where a spin torque oscillator (STO) is integrated with a conventional magnetic tunnel junction (MTJ) which will assist in the ultrafast reversal of the magnetization of the free layer of the MTJ. The structure formed (MTJ stacked with STO), will have the free layer of the MTJ sandwiched between two spin polarizer layers, one with a fixed magnetization direction perpendicular to film plane (main static polarizer) and the other with an oscillatory magnetization (dynamic polarizer). The static polarizer is the fixed layer of the MTJ itself and the dynamic polarizer is the free layer of the STO.

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