Transient magnetization dynamics of spin-torque oscillator and magnetic dot coupled by magnetic dipolar interaction: Reading of magnetization direction using magnetic resonance

2018 ◽  
Vol 123 (4) ◽  
pp. 043903 ◽  
Author(s):  
Taro Kanao ◽  
Hirofumi Suto ◽  
Kiwamu Kudo ◽  
Tazumi Nagasawa ◽  
Koichi Mizushima ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Dipolar Interaction ◽  
Spin Torque ◽  
Magnetization Dynamics ◽  
Magnetization Direction ◽  
Magnetic Dipolar Interaction ◽  
Magnetic Dot

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.

scholarly journals Magnetic dipolar interaction between correlated triplets created by singlet fission in tetracene crystals

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Rui Wang ◽  
Chunfeng Zhang ◽  
Bo Zhang ◽  
Yunlong Liu ◽  
Xiaoyong Wang ◽  
...  
Keyword(s):  
Dipolar Interaction ◽  
Singlet Fission ◽  
Magnetic Dipolar Interaction

scholarly journals Aspects Concerning the Fabrication of Magnetorheological Fluids Containing High Magnetization FeCo Nanoparticles

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 132
Author(s):  
Jon Gutiérrez ◽  
Virginia Vadillo ◽  
Ainara Gómez ◽  
Joanes Berasategi ◽  
Maite Insausti ◽  
...  
Keyword(s):  
Recent Literature ◽  
Chemical Reduction ◽  
Collaborative Work ◽  
Magnetorheological Fluid ◽  
Dipolar Interaction ◽  
Fabrication Process ◽  
Superior Performance ◽  
Strong Trend ◽  
Magnetic Dipolar Interaction ◽  
Feco Nanoparticles

Recently, our collaborative work in the fabrication of a magnetorheological fluid (MRF) containing high magnetization FeCo nanoparticles (NPs, fabricated in our laboratories using the chemical reduction technique; MS = 212 Am2/kg) as magnetic fillers have resulted in a new MRF with superior performance up to 616.7 kA/m. The MRF had a yield stress value of 2729 Pa and good reversibility after a demagnetization process. This value competes with the best ones reported in the most recent literature. Nevertheless, the fabrication process of this type of fluid is not an easy task since there is a strong trend to the aggregation of the FeCo NPs due to the strong magnetic dipolar interaction among them. Thus, now we present the analysis of some aspects concerning the fabrication process of our FeCo NPs containing MRF, mainly the type of surfactant used to cover those NPs (oleic acid or aluminium stearate) and its concentration, and the procedure followed (mechanical and/or ultrasound stirring) to achieve a good dispersion of those magnetic fillers within the fluid.

scholarly journals Microresonators and Microantennas—Tools to Explore Magnetization Dynamics in Single Nanostructures

2021 ◽  
Vol 7 (2) ◽  
pp. 28
Author(s):  
Hamza Cansever ◽  
Jürgen Lindner
Keyword(s):  
Magnetic Resonance ◽  
Spin Wave ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Relaxation Times ◽  
Magnetic Nanostructures ◽  
Microwave Frequency ◽  
Direct Access ◽  
Magnetization Dynamics ◽  
G Factor

The phenomenon of magnetic resonance and its detection via microwave spectroscopy provide insight into the magnetization dynamics of bulk or thin film materials. This allows for direct access to fundamental properties, such as the effective magnetization, g-factor, magnetic anisotropy, and the various damping (relaxation) channels that govern the decay of magnetic excitations. Cavity-based and broadband ferromagnetic resonance techniques that detect the microwave absorption of spin systems require a minimum magnetic volume to obtain a sufficient signal-to-noise ratio (S/N). Therefore, conventional techniques typically do not offer the sensitivity to detect individual micro- or nanostructures. A solution to this sensitivity problem is the so-called planar microresonator, which is able to detect even the small absorption signals of magnetic nanostructures, including spin-wave or edge resonance modes. As an example, we describe the microresonator-based detection of spin-wave modes within microscopic strips of ferromagnetic A2 Fe60Al40 that are imprinted into a paramagnetic B2 Fe60Al40-matrix via focused ion-beam irradiation. While microresonators operate at a fixed microwave frequency, a reliable quantification of the key magnetic parameters like the g-factor or spin relaxation times requires investigations within a broad range of frequencies. Furthermore, we introduce and describe the step from microresonators towards a broadband microantenna approach. Broadband magnetic resonance experiments on single nanostructured magnetic objects in a frequency range of 2–18 GHz are demonstrated. The broadband approach has been employed to explore the influence of lateral structuring on the magnetization dynamics of a Permalloy (Ni80Fe20) microstrip.

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 A cryogenic spin-torque memory element with precessional magnetization dynamics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
G. E. Rowlands ◽  
C. A. Ryan ◽  
L. Ye ◽  
L. Rehm ◽  
D. Pinna ◽  
...  
Keyword(s):  
Spin Torque ◽  
Magnetization Dynamics ◽  
Memory Element

Stability Analysis of Spin-Torque Nano-oscillator in the Rotating Frame

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950008
Author(s):  
HaoHsuan Chen ◽  
Lang Zeng ◽  
ChingMing Lee ◽  
Weisheng Zhao
Keyword(s):  
High Performance ◽  
Electrical Current ◽  
Nonstationary Process ◽  
Laboratory Frame ◽  
Spin Torque ◽  
Rotating Frame ◽  
Magnetization Dynamics ◽  
Applied Current ◽  
Frequency Tunability ◽  
Out Of Plane

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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