scholarly journals Performance characteristics of bistable active ring resonators based on ferrite films

2021 ◽  
Vol 2103 (1) ◽  
pp. 012059
Author(s):  
V V Vitko ◽  
R V Haponchyk ◽  
A A Nikitin ◽  
A B Ustinov

Abstract A bistability phenomenon in a ring resonator consisting of a delay line on surface spin waves and a microwave amplifier has been experimentally investigated. It is shown that an enhancement of the gain coefficient above a specified value provides an appearance of a hysteresis at the resonator transmission characteristic. A frequency range of the bistability broadens due to an increase of the gain coefficient as well as the external magnetic field. While the value of the gain is limited from above by a transition of the ring into a self-oscillating regime, an increase in the magnetic field from 1150 Oe up to 3150 Oe provides an expansion of the frequency range of the hysteresis from 77 kHz to 185 kHz.

1970 ◽  
Vol 48 (3) ◽  
pp. 362-366
Author(s):  
M. Abbas

Absorption of hydromagnetic waves in the ionosphere propagated normal to the magnetic field is calculated at various frequencies and compared with the absorption for parallel propagation. Data corresponding to both daytime and nighttime ionospheres are used. Waves propagated normal to the magnetic field are highly absorbed through the daytime ionosphere at frequencies above a few Hz; the nighttime ionosphere, however, is virtually transparent to waves in the frequency range of 10−3 to 20 Hz. A comparison of the absorption processes for waves propagated parallel and normal to the magnetic field is made.


Author(s):  
Yu.V. Maslennikov ◽  
◽  
◽  

There are a large number of sensors for measuring the magnetic field of biological objects. They are characterized by the type of the measured physical parameter (magnetic field strength, magnetic flux, etc.), the level of intrinsic sensitivity, and the frequency range of the recorded signals. The long-term practice of studying biomagnetic signals shows that only SQUID-based magnetometers and optically pumped magnetometers have sensitivity levels sufficient for recording biomagnetic signals with the required signal-to-noise ratio. This chapter reflects the main directions of using such magnetometers and methods of magnetic measurements in biomedical research, gives examples of existing technical solutions, and shows possible ways of their further development.


1996 ◽  
Vol 160 ◽  
pp. 279-282
Author(s):  
Michael Kramer ◽  
Kiriaki M. Xilouris

AbstractWe report flux density measurements, polarimetric and timing observations of pulsars made at the highest radio frequencies to date, covering the widest frequency range from 1.4 GHz to 86 GHz. We find that the magnetic field maintains its dipolar structure throughout the active part of the magnetosphere, a region located close to the stellar surface and confined to a small slab of a few stellar radii. The change in width and shape of pulse profiles saturates at mm-wavelengths while the depolarization accelerates, leading to almost completely depolarized emission. Two pulsars seem to exhibit a turn-up in their flux density spectrum at mm-wavelengths.


2016 ◽  
Vol 30 (19) ◽  
pp. 1650119
Author(s):  
Yuntuan Fang ◽  
Zhiyao Ni ◽  
Lixia Yang

We propose a new design to achieve optical waveguide switch. We construct a photonic crystal waveguide with one yttrium iron garnet (YIG) rod array on the two sides of the waveguide. Through the mode analysis, we find in special frequency range a few YIG rods under magnetic field can form the magnetic reflectance wall that blocks the light flow. Removing the magnetic field will delete the reflection wall and let the blocked light to be switched on.


Author(s):  
Е.Г. Екомасов ◽  
С.В. Степанов ◽  
В.Н. Назаров ◽  
К.А. Звездин ◽  
Н.Г. Пугач ◽  
...  

The joint effect of the spin polarized current and an external magnetic field on the dynamics of magnetization in vortex spin-transfer nano-oscillators with a diameter of 400 nm is investigated. For the numerical calculation of the coupled dynamics of magnetic vortices, the SpinPM software package for micromagnetic modeling was used. The dependence of the frequency of stationary coupled oscillations of vortices on the magnitude of the magnetic field, which determines the operating frequency range of a tunable vortex spin-transfer nano-oscillator.


Author(s):  
David P. Vallett ◽  
Daniel A. Bader ◽  
Vladimir V. Talanov ◽  
Jan Gaudestad ◽  
Nicolas Gagliolo ◽  
...  

Abstract Space Domain Reflectometry (SDR) is a newly developed non-destructive failure analysis (FA) technique for localizing open defects in both packages and dies through mapping in space domain the magnetic field produced by a radio frequency (RF) current induced in the sample, herein the name Space Domain Reflectometry. The technique employs a scanning superconducting quantum interference device (SQUID) RF microscope operating over a frequency range from 60 to 200 MHz. In this paper we demonstrate that SDR is capable of locating defective micro bumps in a flip-chip device.


Author(s):  
Xiao Ping Li ◽  
Z.J. Zhao ◽  
T.B. Oh ◽  
H.L. Seet

In order to develop high sensitivity micro sensors for bio-magnetic field using NiFe electroplated composite sensing elements, it is important to study how different plating processes can affect the magnetic properties in terms of the chemical composition and magnetic structure of the plated layer. In this study, to study the effect of the magnetic field on the magnetic structure of the electroplated NiFe layers, magnetic controlled plating in which a longitudinal magnetic field ranging from 0 to 400 Oe is applied during nanocrystalline electroplating of permalloy Ni80Fe20 layer of 2 µm thick onto a 20 µm diameter Cu wire. The magnetic structure of the plated layers is studied by investigating the Giant magneto-impedance (GMI) effect of the plated layer. GMI has been measured from a frequency range of 100 kHz to 50 MHz. It is observed that under conventional electroplating without an external magnetic controlling field, the anisotropy of the plated layer is generally circumferential as indicted by the double peaks of the MI curves in testing at high frequency. When a longitudinal magnetic field is applied during electroplating, the plated layer shows single peak MI curves, suggesting that the anisotropy is changed from circumferential to longitudinal. The results also show that the sensitivity and resolution of a magnetic field sensor is improved greatly by changing the anisotropy of the plated layer from circumferential to longitudinal.


2020 ◽  
Vol 10 (5) ◽  
pp. 507
Author(s):  
Redouane Mghaiouini ◽  
Abderahmane Elmalouky ◽  
Nisrine Benzbiria ◽  
Radad El Moznine ◽  
Mohamade Monkade ◽  
...  

<p>This paper presents an experimental study to investigate the effect of using the electromagnetic field on the electric conductivity and dielectric properties of treated tap water by aqua 4 D system according to the time of exposition in a closed water circulation circuit. There is a portion where there is an electromagnetic field obtained by the electromagnetic device. This work includes tap water circulation in the region of the electromagnetic field for 5 min, 10, 15, 20 min. The dielectric and electrical properties were examined and analyzed using the technique impedance spectroscopy in the frequency range going from 0.1 Hz to 1 MHz.</p><p>To initiate the phenomena involving water after magnetization with the electromagnetic field. The results clearly show that the magnetic field reduces the dielectric constant and resistance of water and increase its electric conductivity. In this study, we also find that the electrical conductivity of magnetized water increases.</p>


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