Soft magnetic properties and giant magnetoimpedance effect in thermally annealed amorphous Co68Fe4Cr3Si15B10 alloy ribbons

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.

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Effects of Current Pulsation on Magnetic Properties and Giant Magnetoimpedance of Electrodeposited NiFe Coatings on Cu Wires

Materials Science Forum ◽

10.4028/www.scientific.net/msf.928.235 ◽

2018 ◽

Vol 928 ◽

pp. 235-242 ◽

Cited By ~ 1

Author(s):

Viriyah Chobaomsup ◽

Pongsakorn Jantaratana ◽

Yuttanant Boonyongmaneerat

Keyword(s):

Magnetic Properties ◽

Soft Magnetic Properties ◽

Vibrating Sample Magnetometer ◽

Electrodeposition Technique ◽

Soft Magnetic ◽

Applied Current ◽

Giant Magnetoimpedance ◽

Nickel Iron ◽

Fe Content ◽

Current Pulsation

This work presents a systematic study of the effects of current pulsation on soft magnetic properties and giant magnetoimpedance (GMI) of nickel-iron (NiFe) coatings electrodeposited on copper wires. The specimens were prepared by the electrodeposition technique with controlled bath compositions and varied applied current waveforms. The microstructural and chemical investigations indicate that current pulsation with 50% duty cycle and 50 Hz frequency provides significantly smoother coating surface of uniform nodules, with comparable Fe content but different phase composition, as compared to the direct current condition. The vibrating sample magnetometer evidently shows that the deposits prepared with a pulsed current exhibit relatively small coercivity, below 4 Oe. Using the four-point probe technique, the MI ratio of the pulse deposits is found to reach a significantly high value above 2,000% with decent sensitivity. The benefits of current pulsation in improving the characteristics of NiFe deposits, and correspondingly the alloys’ soft magnetic properties and MI effects are demonstrated.

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Optimization of magnetic properties and GMI effect of Thin Co-rich Microwires for GMI Microsensors

Sensors ◽

10.3390/s20061558 ◽

2020 ◽

Vol 20 (6) ◽

pp. 1558 ◽

Cited By ~ 4

Author(s):

Lorena Gonzalez-Legarreta ◽

Paula Corte-Leon ◽

Valentina Zhukova ◽

Mihail Ipatov ◽

Juan Maria Blanco ◽

...

Keyword(s):

Magnetic Properties ◽

Magnetic Anisotropy ◽

Hysteresis Loops ◽

Transverse Magnetic ◽

Wide Frequency Range ◽

Soft Magnetic ◽

Giant Magnetoimpedance ◽

Giant Magnetoimpedance Effect ◽

Annealing Temperatures ◽

High Annealing

Magnetic microwires can present excellent soft magnetic properties and a giant magnetoimpedance effect. In this paper, we present our last results on the effect of postprocessing allowing optimization of the magnetoimpedance effect in Co-rich microwires suitable for magnetic microsensor applications. Giant magnetoimpedance effect improvement was achieved either by annealing or stress-annealing. Annealed Co-rich presents rectangular hysteresis loops. However, an improvement in magnetoimpedance ratio is observed at fairly high annealing temperatures over a wide frequency range. Application of stress during annealing at moderate values of annealing temperatures and stress allows for a remarkable decrease in coercivity and increase in squareness ratio and further giant magnetoimpedance effect improvement. Stress-annealing, carried out at sufficiently high temperatures and/or stress allowed induction of transverse magnetic anisotropy, as well as magnetoimpedance effect improvement. Enhanced magnetoimpedance ratio values for annealed and stress-annealed samples and frequency dependence of the magnetoimpedance are discussed in terms of the radial distribution of the magnetic anisotropy. Accordingly, we demonstrated that the giant magnetoimpedance effect of Co-rich microwires can be tailored by controlling the magnetic anisotropy of Co-rich microwires, using appropriate thermal treatment.

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Magnetic Properties and the Giant Magneto-Impedance in Joule-Heated Glass-Covered Co-Based Microwire

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1407 ◽

2009 ◽

Vol 79-82 ◽

pp. 1407-1410 ◽

Cited By ~ 3

Author(s):

B. Tian ◽

L.H. Wang ◽

L.Y. Zhou

Keyword(s):

Magnetic Properties ◽

Induced Anisotropy ◽

Soft Magnetic ◽

Applied Current ◽

Giant Magnetoimpedance ◽

Maximum Slope ◽

Giant Magnetoimpedance Effect ◽

Amorphous Microwires ◽

Dc Current ◽

Heated Glass

The influence of DC current annealing on magnetic properties and the frequency dependence in the range from 0.1 to 20 MHz of the giant magnetoimpedance effect (GMI) of glass-covered amorphous microwires were investigated. Under a certain annealing condition (10 min annealing with applied current Ia=110 mA), the maximum change of impedance was about 200% with a maximum slope sensitivity of 0.26%/Am-1 . Further treatment with increased current resulted in a decrease of the maximum MI ratio. Meanwhile, annealing can produce short-range order relaxation and consequently improves the sample's soft magnetic properties. We also found that the GMI ratio increased due to the enhanced induced anisotropy with increasing current under the same Joule energy.

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