scholarly journals Performance Optimization of Spin-Torque Microwave Detectors with Material and Operational Parameters

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
X. Li ◽  
Y. Zhou ◽  
Philip W. T. Pong
Keyword(s):  
Magnetic Field ◽  
Tilt Angle ◽  
Performance Optimization ◽  
Effective Field ◽  
Performance Tuning ◽  
Spin Torque ◽  
Operational Parameters ◽  
Equilibrium Angle ◽  
Reference Layer ◽  
Layer Magnetization

Sensitivity, bandwidth, and noise equivalent power (NEP) are important indicators of the performance of microwave detectors. The previous reports on spin-torque microwave detectors (STMDs) have proposed various approaches to increase the sensitivity. However, the effects of these methods on the other two indicators remain unclear. In this work, macrospin simulation is developed to evaluate how the performance can be optimized through changing the material (tilt angle of reference-layer magnetization) and operational parameters (the direction of magnetic field and working temperature). The study on the effect of magnetic field reveals that the driving force behind the performance tuning is the effective field and the equilibrium angle between the magnetization of the free layer and that of the reference layer. The material that offers the optimal tilt angle in reference-layer magnetization is determined. The sensitivity can be further increased by changing the direction of the applied magnetic field and the operation temperature. Although the optimized sensitivity is accompanied by a reduction in bandwidth or an increase in NEP, a balance among these performance indicators can be reached through optimal tuning of the corresponding influencing parameters.

scholarly journals In-Orbit Operational Parameter Calculation and Performance Optimization in KOMPSAT-6 Synthetic Aperture Radar

2021 ◽  
Vol 13 (12) ◽  
pp. 2342
Author(s):  
Jin-Bong Sung ◽  
Sung-Yong Hong
Keyword(s):  
Synthetic Aperture Radar ◽  
Performance Optimization ◽  
Pulse Repetition Frequency ◽  
Optimization Method ◽  
Synthetic Aperture ◽  
Operational Parameters ◽  
Operational Parameter ◽  
Design Methodologies ◽  
And Performance ◽  
Aperture Radar

A new method to design in-orbit synthetic aperture radar operational parameters has been implemented for the Korean Multi-purpose Satellite 6 mission. The implemented method optimizes the pulse repetition frequency when a satellite altitude changes from its nominal one, so it has the advantage that the synthetic aperture radar performances can satisfy the requirements for the in-orbit operation. Other commanding parameters have been designed to conduct trade-off between those parameters. This paper presents the new optimization method to maintain the synthetic aperture radar performances even in the case of an altitude variation. Design methodologies to determine operational parameters, respectively, at nominal altitude and in orbit are presented. In addition, numerical simulation is presented to validate the proposed optimization and the design methodologies.

scholarly journals Controllable field-free switching of perpendicular magnetization through bulk spin-orbit torque in symmetry-broken ferromagnetic films

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuejie Xie ◽  
Xiaonan Zhao ◽  
Yanan Dong ◽  
Xianlin Qu ◽  
Kun Zheng ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Domain Walls ◽  
Single Layer ◽  
Ferromagnetic Film ◽  
Effective Field ◽  
Composition Gradient ◽  
Spin Orbit ◽  
Interlayer Exchange Coupling ◽  
Magnetization Switching ◽  
Perpendicular Magnetization

AbstractProgrammable magnetic field-free manipulation of perpendicular magnetization switching is essential for the development of ultralow-power spintronic devices. However, the magnetization in a centrosymmetric single-layer ferromagnetic film cannot be switched directly by passing an electrical current in itself. Here, we demonstrate a repeatable bulk spin-orbit torque (SOT) switching of the perpendicularly magnetized CoPt alloy single-layer films by introducing a composition gradient in the thickness direction to break the inversion symmetry. Experimental results reveal that the bulk SOT-induced effective field on the domain walls leads to the domain walls motion and magnetization switching. Moreover, magnetic field-free perpendicular magnetization switching caused by SOT and its switching polarity (clockwise or counterclockwise) can be reversibly controlled in the IrMn/Co/Ru/CoPt heterojunctions based on the exchange bias and interlayer exchange coupling. This unique composition gradient approach accompanied with electrically controllable SOT magnetization switching provides a promising strategy to access energy-efficient control of memory and logic devices.

scholarly journals Magnetophonons & type-B Goldstones from hydrodynamics to holography

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Matteo Baggioli ◽  
Sebastian Grieninger ◽  
Li Li
Keyword(s):  
Magnetic Field ◽  
2D Materials ◽  
Goldstone Boson ◽  
Quasinormal Modes ◽  
Effective Field ◽  
Zero Magnetic Field ◽  
Type B ◽  
Hydrodynamic Modes ◽  
Pinning Mechanism ◽  
The Magnetic Field

Abstract We perform a detailed analysis of a large class of effective holographic models with broken translations at finite charge density and magnetic field. We exhaustively discuss the dispersion relations of the hydrodynamic modes at zero magnetic field and successfully match them to the predictions from charged hydrodynamics. At finite magnetic field, we identify the presence of an expected type-B Goldstone boson Re[ω] ∼ k2, known as magnetophonon and its gapped partner — the magnetoplasmon. We discuss their properties in relation to the effective field theory and hydrodynamics expectations. Finally, we compute the optical conductivities and the quasinormal modes at finite magnetic field. We observe that the pinning frequency of the magneto-resonance peak increases with the magnetic field, in agreement with experimental data on certain 2D materials, revealing the quantum nature of the holographic pinning mechanism.

Parameters controlling the substorm onset location

2021 ◽  
Author(s):  
Reham Elhawary ◽  
Karl Laundal ◽  
Jone Reistad ◽  
Anders Ohma ◽  
Spencer Hatch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Tilt Angle ◽  
Linear Regression Analysis ◽  
Substorm Onset ◽  
Azimuthal Component ◽  
Field Orientation ◽  
Hall Conductance ◽  
Onset Location ◽  
Dipole Tilt

<p>Substorm onset location varies over a range of magnetic local time (MLT) and magnetic latitudes (MLat). It is well known that about 5% of the variation in onset MLT can be explained by variations in interplanetary magnetic field orientation and dipole tilt angle. Both parameters introduce an azimuthal component in the magnetic field in the magnetosphere such that the projection of the onset MLT in the ionosphere is shifted. The MLT of the onset near the magnetopsheric equatorial plane is even less predictable. Recent studies have suggested that gradients in the ionospheric Hall conductance lead to a duskward shift of tail dynamics, which could also influence the location of substorm onset. Our goal is to test these ideas by quantifying the dependence of the spatial variation of the onset location on external and internal conditions. We focus on the correlation between the substorm onset location with conditions prior to the onset, such as the interplanetary magnetic field By component, dipole tilt angle, and estimates of the Hall conductance. Linear regression analysis is used to determine the substorm onset location dependence on the proposed variables.</p>

Sign in / Sign up

Export Citation Format

Share Document