Modeling of spin-torque driven magnetization dynamics in a spin-valve with combined in-plane and out-of-plane polarizers

Spin-torque nano-oscillators (STNOs) have become one of the emerging and novel microwave devices with the high performance and tunability of GHz range frequency. The nanopillar structure with an out-of-plane (OP) spin polarizer and an in-plane (IP) magnetized free layer (FL) has been considered as a good candidate for the STNOs. Using the local rotational coordinate transformation, a nonstationary process describing magnetization dynamics in the laboratory frame is therefore transformed into a stationary one in the rotating frame. In this way, the state phase diagram of this type of STNOs is well established as a function of an applied current and external field, which is also evidenced by the macrospin simulations. Also, we show that the frequency tunability of the STNOs through electrical current can be well elevated by applying a static magnetic field anti-parallel to the spin-polarizer vector.

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Effective Hamiltonian for silicene under arbitrary strain from multi-orbital basis

Scientific Reports ◽

10.1038/s41598-021-86947-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhuo Bin Siu ◽

Mansoor B. A. Jalil

Keyword(s):

Tight Binding ◽

Spin Torque ◽

Spin Accumulation ◽

Effective Hamiltonian ◽

Fermi Surfaces ◽

Orbital Basis ◽

Lattice Symmetry ◽

Out Of Plane ◽

Coupling Parameters ◽

Spin Orbit Interactions

AbstractA tight-binding (TB) Hamiltonian is derived for strained silicene from a multi-orbital basis. The derivation is based on the Slater–Koster coupling parameters between different orbitals across the silicene lattice and takes into account arbitrary distortion of the lattice under strain, as well as the first and second-order spin–orbit interactions (SOI). The breaking of the lattice symmetry reveals additional SOI terms which were previously neglected. As an exemplary application, we apply the linearized low-energy TB Hamiltonian to model the current-induced spin accumulation in strained silicene coupled to an in-plane magnetization. The interplay between symmetry-breaking and the additional SOI terms induces an out-of-plane spin accumulation. This spin accumulation remains unbalanced after summing over the Fermi surfaces of the occupied bands and the two valleys, and can thus be utilized for spin torque switching.

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Route towards efficient magnetization reversal driven by voltage control of magnetic anisotropy

Scientific Reports ◽

10.1038/s41598-021-88408-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Roxana-Alina One ◽

Hélène Béa ◽

Sever Mican ◽

Marius Joldos ◽

Pedro Brandão Veiga ◽

...

Keyword(s):

Magnetic Anisotropy ◽

Random Access ◽

Low Power Consumption ◽

Surface Anisotropy ◽

Magnetization Dynamics ◽

Storage Density ◽

Switching Regime ◽

Major Interest ◽

Out Of Plane

AbstractThe voltage controlled magnetic anisotropy (VCMA) becomes a subject of major interest for spintronics due to its promising potential outcome: fast magnetization manipulation in magnetoresistive random access memories with enhanced storage density and very low power consumption. Using a macrospin approach, we carried out a thorough analysis of the role of the VCMA on the magnetization dynamics of nanostructures with out-of-plane magnetic anisotropy. Diagrams of the magnetization switching have been computed depending on the material and experiment parameters (surface anisotropy, Gilbert damping, duration/amplitude of electric and magnetic field pulses) thus allowing predictive sets of parameters for optimum switching experiments. Two characteristic times of the trajectory of the magnetization were analyzed analytically and numerically setting a lower limit for the duration of the pulses. An interesting switching regime has been identified where the precessional reversal of magnetization does not depend on the voltage pulse duration. This represents a promising path for the magnetization control by VCMA with enhanced versatility.

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

IEEE Transactions on Magnetics ◽

10.1109/tmag.2018.2829220 ◽

2018 ◽

Vol 54 (11) ◽

pp. 1-4 ◽

Cited By ~ 2

Author(s):

Y. Nakamura ◽

M. Nishikawa ◽

H. Osawa ◽

Y. Okamoto ◽

T. Kanao ◽

...

Keyword(s):

Spin Torque ◽

Magnetization Dynamics ◽

Snr Improvement

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Precession frequency and fast switching dependence on the in-plane and out-of-plane dual spin-torque polarizers

Applied Physics Letters ◽

10.1063/1.3700724 ◽

2012 ◽

Vol 100 (14) ◽

pp. 142409 ◽

Cited By ~ 14

Author(s):

Hong Zhang ◽

Zhiwei Hou ◽

Jianwei Zhang ◽

Zongzhi Zhang ◽

Yaowen Liu

Keyword(s):

Precession Frequency ◽

Spin Torque ◽

Fast Switching ◽

Out Of Plane

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Optically excited spin pumping mediating collective magnetization dynamics in a spin valve structure

Physical Review B ◽

10.1103/physrevb.98.060406 ◽

2018 ◽

Vol 98 (6) ◽

Cited By ~ 4

Author(s):

A. P. Danilov ◽

A. V. Scherbakov ◽

B. A. Glavin ◽

T. L. Linnik ◽

A. M. Kalashnikova ◽

...

Keyword(s):

Spin Valve ◽

Magnetization Dynamics ◽

Spin Pumping ◽

Valve Structure

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

Sultan Qaboos University Journal for Science [SQUJS] ◽

10.24200/squjs.vol25iss1pp54-60 ◽

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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