scholarly journals Controlled nonlinear magnetic damping in spin-Hall nano-devices

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Boris Divinskiy ◽  
Sergei Urazhdin ◽  
Sergej O. Demokritov ◽  
Vladislav E. Demidov
Keyword(s):  
Spin Current ◽  
Nonlinear Damping ◽  
Nonlinear Phenomena ◽  
Linear Regime ◽  
Magnetization Dynamics ◽  
Magnetic Disk ◽  
Magnetic Damping ◽  
Spatially Extended ◽  
Magnetization Precession ◽  
Low Amplitude

AbstractLarge-amplitude magnetization dynamics is substantially more complex compared to the low-amplitude linear regime, due to the inevitable emergence of nonlinearities. One of the fundamental nonlinear phenomena is the nonlinear damping enhancement, which imposes strict limitations on the operation and efficiency of magnetic nanodevices. In particular, nonlinear damping prevents excitation of coherent magnetization auto-oscillations driven by the injection of spin current into spatially extended magnetic regions. Here, we propose and experimentally demonstrate that nonlinear damping can be controlled by the ellipticity of magnetization precession. By balancing different contributions to anisotropy, we minimize the ellipticity and achieve coherent magnetization oscillations driven by spatially extended spin current injection into a microscopic magnetic disk. Our results provide a route for the implementation of efficient active spintronic and magnonic devices driven by spin current.

scholarly journals Evidence for spin current driven Bose-Einstein condensation of magnons

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Divinskiy ◽  
H. Merbouche ◽  
V. E. Demidov ◽  
K. O. Nikolaev ◽  
L. Soumah ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Potential ◽  
Spin Current ◽  
Einstein Condensation ◽  
Electronic Control ◽  
Spintronic Devices ◽  
Bose Einstein Condensation ◽  
Magnetic Insulators ◽  
Spatially Extended ◽  
Bose Einstein

AbstractThe quanta of magnetic excitations – magnons – are known for their unique ability to undergo Bose-Einstein condensation at room temperature. This fascinating phenomenon reveals itself as a spontaneous formation of a coherent state under the influence of incoherent stimuli. Spin currents have been predicted to offer electronic control of Bose-Einstein condensates, but this phenomenon has not been experimentally evidenced up to now. Here we show that current-driven Bose-Einstein condensation can be achieved in nanometer-thick films of magnetic insulators with tailored nonlinearities and minimized magnon interactions. We demonstrate that, above a certain threshold, magnons injected by the spin current overpopulate the lowest-energy level forming a highly coherent spatially extended state. We quantify the chemical potential of the driven magnon gas and show that, at the critical current, it reaches the energy of the lowest magnon level. Our results pave the way for implementation of integrated microscopic quantum magnonic and spintronic devices.

Modulation of magnetization dynamics in an epitaxial Heusler ferromagnet due to pure spin current in a laterally configured structure

2018 ◽  
Vol 30 (25) ◽  
pp. 255802
Author(s):  
Soichiro Oki ◽  
Yuta Sasaki ◽  
Yuichi Kasatani ◽  
Shinya Yamada ◽  
Shigemi Mizukami ◽  
...  
Keyword(s):  
Spin Current ◽  
Pure Spin ◽  
Magnetization Dynamics

Laser-Induced Magnetization Dynamics of GdFeCo Film Probing by Time Resolved Magneto-Optic Kerr Effect

SPIN ◽  
2015 ◽  
Vol 05 (04) ◽  
pp. 1540014 ◽  
Author(s):  
Wei He ◽  
Hong-Ye Wu ◽  
Jian-Wang Cai ◽  
Yao-Wen Liu ◽  
Zhao-Hua Cheng
Keyword(s):  
Diffusion Coefficient ◽  
Kerr Effect ◽  
Recovery Process ◽  
Optical Effect ◽  
Magnetization Dynamics ◽  
Time Resolved ◽  
Thermal Diffusion Coefficient ◽  
Magneto Optical Effect ◽  
Magnetization Orientation ◽  
Magnetization Precession

Laser-induced magnetization dynamics in Gd[Formula: see text]Fe[Formula: see text]Co[Formula: see text] (GdFeCo) film was investigated by time-resolved magneto-optical effect. After an ultrafast demagnetization and a magnetization recovery process, a second slower drop from several picoseconds (ps) to 200[Formula: see text]ps was observed. Previous report explained it as the demagnetization of Gd sublattice. However, when timescale extended up to 5 nanosecond (ns), we identified it as the part of an oscillated magnetization precession. It presents the change of magnetization orientation rather than the change of magnetization amplitude. Our results reveal that the low thermal diffusion coefficient of GdFeCo film plays an important role in the laser-induced magnetization dynamics of GdFeCo film.

scholarly journals Spin-Current Manipulation of Photo-Induced Magnetization Dynamics in Heavy Metal/Ferromagnet Double Layer-Based Nanostructures

2017 ◽  
Vol 53 (11) ◽  
pp. 1-4
Author(s):  
Steffen Wittrock ◽  
Dennis Meyer ◽  
Markus Muller ◽  
Henning Ulrichs ◽  
Jakob Walowski ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Double Layer ◽  
Spin Current ◽  
Magnetization Dynamics

scholarly journals Dynamic analysis and experiment of QZS system with nonlinear hysteretic damping

2021 ◽  
Author(s):  
Xiaoying Hu ◽  
Chunyan Zhou
Keyword(s):  
Vibration Isolation ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Primary Response ◽  
Nonlinear Phenomena ◽  
Isolation Frequency ◽  
Hysteretic Damping ◽  
Isolation Systems ◽  
The One ◽  
Vibration Tests

Abstract Nonlinear Quasi-zero-stiffness (QZS) vibration isolation systems with linear damping cannot lead to displacement isolation with different excitation levels. In this study, a QZS system with nonlinear hysteretic damping was investigated. The Duffing-Ueda equation with a coupling nonlinear parameter 𝜂 was proposed to describe the dynamic motion of the QZS system. By using the harmonic balance method (HBM), the primary and secondary harmonic responses were obtained and verified by numerical simulations. The results indicated that nonlinear damping can guarantee a bounded response for different excitation levels. The one-third subharmonic response was found to affect the isolation frequency range even when the primary response was stable. To evaluate the performance of the QZS system, the effective isolation frequency Ω𝑒 and maximum transmissibility 𝑇𝑝 were proposed to represent the vibration isolation range and isolation effect, respectively. By discussing the effect of 𝜂 on Ω𝑒 and 𝑇𝑝, the conditions to avoid nonlinear phenomena and improve the isolation performance are provided. A prototype of the QZS system was then constructed for vibration tests, which verified the theoretical analysis.

scholarly journals Giant nonlinear damping in nanoscale ferromagnets

2019 ◽  
Vol 5 (10) ◽  
pp. eaav6943 ◽  
Author(s):  
I. Barsukov ◽  
H. K. Lee ◽  
A. A. Jara ◽  
Y.-J. Chen ◽  
A. M. Gonçalves ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
High Resolution ◽  
Nonlinear Damping ◽  
Spin Torque ◽  
Magnetic Dynamics ◽  
Magnetic Damping ◽  
Microwave Magnetic Field ◽  
Geometric Confinement ◽  
Phenomenological Constant

Magnetic damping is a key metric for emerging technologies based on magnetic nanoparticles, such as spin torque memory and high-resolution biomagnetic imaging. Despite its importance, understanding of magnetic dissipation in nanoscale ferromagnets remains elusive, and the damping is often treated as a phenomenological constant. Here, we report the discovery of a giant frequency-dependent nonlinear damping that strongly alters the response of a nanoscale ferromagnet to spin torque and microwave magnetic field. This damping mechanism originates from three-magnon scattering that is strongly enhanced by geometric confinement of magnons in the nanomagnet. We show that the giant nonlinear damping can invert the effect of spin torque on a nanomagnet, leading to an unexpected current-induced enhancement of damping by an antidamping torque. Our work advances the understanding of magnetic dynamics in nanoscale ferromagnets and spin torque devices.

Spin-current manipulation of photoinduced magnetization dynamics in Ta/CoFeB based nanostructures

2017 ◽  
Author(s):  
S. Wittrock ◽  
D. Meyer ◽  
M. Muller ◽  
H. Ulrichs ◽  
J. Walowski ◽  
...  
Keyword(s):  
Spin Current ◽  
Magnetization Dynamics ◽  
Photoinduced Magnetization

scholarly journals Optimal control of stochastic magnetization dynamics by spin current

2013 ◽  
Vol 102 (4) ◽  
pp. 47001 ◽  
Author(s):  
Yong Wang ◽  
Fu-Chun Zhang
Keyword(s):  
Optimal Control ◽  
Spin Current ◽  
Magnetization Dynamics

Optimum condition for spin-current generation from magnetization precession in thin film systems

2009 ◽  
Vol 94 (15) ◽  
pp. 152509 ◽  
Author(s):  
K. Ando ◽  
T. Yoshino ◽  
E. Saitoh
Keyword(s):  
Thin Film ◽  
Optimum Condition ◽  
Spin Current ◽  
Current Generation ◽  
Magnetization Precession

scholarly journals Major Effective-damping Reduction Achieved by Metallic Coating on YIG Thin Films

2021 ◽  
Author(s):  
E. Hermanny ◽  
D. E. González-Chávez ◽  
R. L. Sommer
Keyword(s):  
Thin Films ◽  
Power Efficiency ◽  
Metal Layer ◽  
Phase Locking ◽  
Spin Current ◽  
Magnetic Damping ◽  
Ferromagnetic Thin Films ◽  
Charge Current ◽  
Nonzero Spin ◽  
Iron Garnet

Abstract Since its discovery, yttrium iron garnet (YIG) has been object of great interest because of its peculiarly low magnetic damping. Magnetic materials with reduced damping promote microwave power efficiency, longer magnon lifetime and longer spin-wave propagation. Owing to research on charge-to-spin current conversion, the control of magnetic damping in ferromagnetic thin films has recently been achieved by inducing charge current on adjacent metal layer with strong spin-orbit coupling (SOC). We report damping reduction in metallized YIG thin films (YIG/Ag/Ni) without the need of applied charge current and suggest that the origin of this unexpected effect is a strengthening of the FMR uniform mode in the YIG layer, due to frequency- and phase-locking that result from self-synchronization mediated by nonzero spin densities transiting the metallic layers.

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