scholarly journals GMI Effect of Ultra-Soft Magnetic Soft Amorphous Microwires

2012 ◽  
Vol 6 (1) ◽  
pp. 39-43 ◽  
Author(s):  
A. Zhukov ◽  
M. Ipatov ◽  
J. M. Blanco ◽  
V. Zhukova
Keyword(s):  
Magnetic Field ◽  
Magnetic Behavior ◽  
Bias Current ◽  
Soft Magnetic ◽  
Magnetoelastic Anisotropy ◽  
Gmi Effect ◽  
Low Field ◽  
Amorphous Microwires

In this paper we experimentally studied GMI effect and soft magnetic behavior of Co-rich microwires. Correlation between magnetoelastic anisotropy and magnetic field dependences of diagonal and off-diagonal impedance components are observed. Low field GMI hysteresis, explained in terms of magnetoelastic anisotropy of microwires, has been suppressed by the bias current.

scholarly journals Development of Magnetic Microwires for Magnetic Sensor Applications

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4767 ◽  
Author(s):  
Valentina Zhukova ◽  
Paula Corte-Leon ◽  
Mihail Ipatov ◽  
Juan Maria Blanco ◽  
Lorena Gonzalez-Legarreta ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Hysteresis Loops ◽  
Magnetic Sensor ◽  
Internal Stresses ◽  
Soft Magnetic ◽  
Magnetoelastic Anisotropy ◽  
Sensor Applications ◽  
Gmi Effect ◽  
Magnetic Softness ◽  
Magnetic Wires

Thin magnetic wires can present excellent soft magnetic properties (with coercivities up to 4 A/m), Giant Magneto-impedance effect, GMI, or rectangular hysteresis loops combined with quite fast domain wall, DW, propagation. In this paper we overview the magnetic properties of thin magnetic wires and post-processing allowing optimization of their magnetic properties for magnetic sensor applications. We concluded that the GMI effect, magnetic softness or DW dynamics of microwires can be tailored by controlling the magnetoelastic anisotropy of as-prepared microwires or controlling their internal stresses and domain structure by appropriate thermal treatment.

scholarly journals Comparing the signal enhancement of a gadolinium based and an iron-oxide based contrast agent in low-field MRI

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256252
Author(s):  
Jordy K. van Zandwijk ◽  
Frank F. J. Simonis ◽  
Friso G. Heslinga ◽  
Elfi I. S. Hofmeijer ◽  
Robert H. Geelkerken ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contrast Agent ◽  
Spin Echo ◽  
Magnetic Behavior ◽  
Positive Contrast ◽  
Mri Contrast Agents ◽  
Signal Enhancement ◽  
Low Field ◽  
Low Field Mri ◽  
Field Strengths

Recently, there has been a renewed interest in low-field MRI. Contrast agents (CA) in MRI have magnetic behavior dependent on magnetic field strength. Therefore, the optimal contrast agent for low-field MRI might be different from what is used at higher fields. Ultra-small superparamagnetic iron-oxides (USPIOs), commonly used as negative CA, might also be used for generating positive contrast in low-field MRI. The purpose of this study was to determine whether an USPIO or a gadolinium based contrast agent is more appropriate at low field strengths. Relaxivity values of ferumoxytol (USPIO) and gadoterate (gadolinium based) were used in this research to simulate normalized signal intensity (SI) curves within a concentration range of 0–15 mM. Simulations were experimentally validated on a 0.25T MRI scanner. Simulations and experiments were performed using spin echo (SE), spoiled gradient echo (SGE), and balanced steady-state free precession (bSSFP) sequences. Maximum achievable SIs were assessed for both CAs in a range of concentrations on all sequences. Simulations at 0.25T showed a peak in SIs at low concentrations ferumoxytol versus a wide top at higher concentrations for gadoterate in SE and SGE. Experiments agreed well with the simulations in SE and SGE, but less in the bSSFP sequence due to overestimated relaxivities in simulations. At low magnetic field strengths, ferumoxytol generates similar signal enhancement at lower concentrations than gadoterate.

scholarly journals Development of Magnetically Soft Amorphous Microwires for Technological Applications

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 26
Author(s):  
Valentina Zhukova ◽  
Paula Corte-Leon ◽  
Juan Maria Blanco ◽  
Mihail Ipatov ◽  
Lorena Gonzalez-Legarreta ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Joule Heating ◽  
Hysteresis Loops ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Magnetic Microwires ◽  
Gmi Effect ◽  
Magnetic Softness ◽  
Order Of Magnitude ◽  
Amorphous Microwires

Amorphous magnetic microwires can be suitable for a variety of technological applications due to their excellent magnetic softness and giant magnetoimpedance (GMI) effect. Several approaches for optimization of soft magnetic properties and GMI effect of magnetic microwires covered with an insulating, flexible, and biocompatible glass coating with tunable magnetic properties are overviewed. The high GMI effect and soft magnetic properties, achieved even in as-prepared Co-rich microwires with a vanishing magnetostriction coefficient, can be further improved by appropriate heat treatment (including stress-annealing and Joule heating). Although as-prepared Fe-rich amorphous microwires exhibit low GMI ratio and rectangular hysteresis loops, stress-annealing, Joule heating, and combined stress-annealed followed by conventional furnace annealing can substantially improve the GMI effect (by more than an order of magnitude).

scholarly journals Direct Magnetoelectric Effect in a Sandwich Structure of PZT and Magnetostrictive Amorphous Microwires

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 916 ◽  
Author(s):  
Abdulkarim Amirov ◽  
Irina Baraban ◽  
Larissa Panina ◽  
Valeria Rodionova
Keyword(s):  
Magnetic Field ◽  
Small Volume ◽  
Magnetoelectric Effect ◽  
Thermoelastic Stress ◽  
Stress Release ◽  
Soft Magnetic ◽  
Multilayered Films ◽  
Soft Magnetic Alloys ◽  
Amorphous Microwires ◽  
Electromechanical Resonance

The magnetoelectric (ME) response in a trilayer structure consisting of magnetostrictive Fe77.5B15Si17.5 amorphous microwires between two piezoelectric PZT (PbZr0.53Ti0.47O3) layers was investigated. Soft magnetic properties of wires make it possible to operate under weak bias magnetic fields below 400 A/m. Enhanced ME voltage coefficients were found when the microwires were excited by ac magnetic field of a frequency of 50–60 kHz, which corresponded to the frequency of electromechanical resonance. The as-prepared microwires were in a glass coat creating a large thermoelastic stress and forming a uniaxial magnetic anisotropy. The effect of glass-coat removal and wire annealing on ME coupling was investigated. The glass coat not only affects the wire magnetic structure but also prevents the interfacial bonding between the electric and magnetic subsystems. However, after its removal, the ME coefficient increased slightly less than 10%. Refining the micromagnetic structure and increasing the magnetostriction by stress release during wire annealing (before or after glass removal) strongly increases the ME response up to 100 mV/(cm × Oe) and reduces the characteristic DC magnetic field down to 240 A/m. Although the achieved ME coefficient is smaller than reported values for multilayered films with layers of PZT and soft magnetic alloys as Metglass, the proposed system is promising considering a small volume proportion of microwires.

THE GIANT MAGNETOSTRICTION AND MAGNETIC PROPERTIES OF THE AMORPHOUS ALTERNANT [Tb/Fe/Dy]n AND [Fe/Tb/Fe/Dy]m NANO-MULTILAYER FILMS

2008 ◽  
Vol 15 (05) ◽  
pp. 619-623
Author(s):  
X. D. LI ◽  
L. K. PAN ◽  
Z. J. ZHAO ◽  
S. M. HUANG ◽  
Y. W. CHEN ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Domain Wall Motion ◽  
Magnetic Behavior ◽  
Multilayer Films ◽  
Film Plane ◽  
Soft Magnetic ◽  
Low Field ◽  
Giant Magnetostriction

The magnetic properties and giant magnetostriction effect (GMS) of the amorphous alternant [ Tb / Fe / Dy ]n (named S1) and [ Fe / Tb / Fe / Dy ]m (named S2) nano-multilayer films have been studied. The magnetic hysteresis loops show that easy magnetic direction changes from perpendicular to the film plane (S1) to parallel to the film plane (S2). S2 has better soft magnetic properties and low-field giant magnetostriction effect than that of S1, due to the exchanging interaction between the hard GMS layer and the soft layer Fe . The different magnetic behavior is explained by considering the nature of the magnetization process, i.e. domain-wall motion and spin rotation.

Giant Magneto-Impedance (GMI) Effect in Single-Layer Soft Magnetic Film Under Stress

2018 ◽  
Vol 18 (12) ◽  
pp. 8195-8200 ◽  
Author(s):  
L Zhu ◽  
F Jin ◽  
Y. Q Zhu ◽  
J. C Wang ◽  
K. F Dong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Layer ◽  
Magnetic Film ◽  
Measurement Range ◽  
Impedance Change ◽  
Soft Magnetic ◽  
Current Frequency ◽  
Gmi Effect ◽  
Giant Magneto Impedance ◽  
Soft Magnetic Film

The stress-induced magnetic anisotropy can significantly affect giant magneto-impedance (GMI) effect of the soft magnetic film. This paper is devoted to the GMI effect of the single layer soft magnetic film implied without and with a stress. By simulating a physical model with MATLAB and COMSOL software, the impedance expression of the single layer soft magnetic film and the relation between external magnetic field and magnetic permeability are deduced. We observed that, without a stress, the sensitive region increased firstly and then decreased with the increasing of the excitation current frequency from 1 MHz to 200 MHz. While the film was subjected to the stress in the direction of the current with one end stressed, the stress on the film was gradually reduced from stressed end to free end. Also, the impedance change rate of the film changed when the stress was added, which is similar to the effect of adding a bias magnetic field on the film. More importantly, the addition of stress σ can induce the bias of the GMI measurement range and improve its sensitivity near zero magnetic fields. This may provide a new way for designing a GMI sensor with higher sensitivity and adjustable measurement range.

scholarly journals Frequency and Magnetic Field Dependence of the Skin Depth in Co-rich Soft Magnetic Microwires

2016 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
A. Zhukov ◽  
A. Talaat ◽  
M. Ipatov ◽  
A. Granovsky ◽  
V. Zhukova
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Magnetic Field Dependence ◽  
Skin Depth ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Giant Magnetoimpedance ◽  
Gmi Effect ◽  
Extended Frequency Range ◽  
Extended Frequency

We studied giant magnetoimpedance (GMI) effect in magnetically soft amorphous Co-rich microwires in the extended frequency range. From obtained experimentally dependences of GMI ratio on magnetic field and different frequencies we estimated the penetration depth and its dependence on applied magnetic field and frequency

scholarly journals Engineering of giant magnetoimpedance effect of amorphous and nanocrystalline microwires

2016 ◽  
Vol 5 (3) ◽  
pp. 63
Author(s):  
V. Zhukova ◽  
A. Talaat ◽  
M. Ipatov ◽  
A. Granovsky ◽  
A. Zhukov
Keyword(s):  
Magnetic Properties ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Giant Magnetoimpedance ◽  
Magnetoelastic Anisotropy ◽  
Giant Magnetoimpedance Effect ◽  
Factors Affecting ◽  
Gmi Effect ◽  
Magnetic Softness

We present our studies of the factors affecting soft magnetic properties and giant magnetoimpedance effect in thin amorphous and nanocrystalline microwires. We showed that the magnetoelastic anisotropy is one of the most important parameters that determine magnetic softness and GMI effect of glass-coated microwires  and annealing can be very effective for manipulation the magnetic properties of amorphous ferromagnetic glass-coated microwires. Considerable magnetic softening and increasing of the GMI effect is observed in Fe-rich nanocrystalline FINEMET-type glass-coated microwires after the nanocrystallization.

Nanocrystalline Soft Magnetic Cores in Applications

2005 ◽  
Vol 473-474 ◽  
pp. 459-464 ◽  
Author(s):  
R. Juhász ◽  
S. Szabó ◽  
Z. Kátai ◽  
F. Bakos ◽  
Dezső L. Beke
Keyword(s):  
Magnetic Field ◽  
Magnetic Materials ◽  
Magnetic Behavior ◽  
Induced Anisotropy ◽  
Soft Magnetic ◽  
Magnetic Parameters ◽  
On Demand ◽  
Magnetic Cores ◽  
Wide Range ◽  
Macroscopic Parameters

Finemet type materials show extremely soft magnetic behavior with excellent and in wide range on-demand variable macroscopic parameters [1]. Requirements for the most important magnetic parameters (e.g. permeability, coercitive force, saturation, loss) are determined by the targeted applications. We report results on the optimization of crystallization treatments and parameter tailoring by magnetic field induced anisotropy. As compared to the most widely used magnetic materials our samples have parameters of real measure of excellence.

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