Giant magneto-impedance effect in diamagnetic organic thin film coated amorphous ribbons

Peksöz, Ahmet; Kaya, Yunus; Taysioglu, A. A.; Derebasi, Naim; Kaynak, Gönül

doi:10.1016/j.sna.2010.03.002

Cited by 28 publications

(9 citation statements)

References 13 publications

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“…8 Peksoz et al recently reported that the coating of the Co-based ribbon surface with CuO or a diamagnetic organic thin film improved the GMI effect. 9,10 While the origin of the enhanced GMI effect in the samples 9,10 is not well understood, these investigations open up new opportunities for improving GMI effect in soft ferromagnetic ribbons.…”

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confidence: 99%

Enhanced giant magnetoimpedance effect and field sensitivity in Co-coated soft ferromagnetic amorphous ribbons

Laurita

Chaturvedi

Bauer

et al. 2011

Journal of Applied Physics

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A 50 nm-thick Co film has been grown either on the free surface (surface roughness, $6 nm) or on the wheel-side surface (surface roughness, $147 nm) of Co 84.55 Fe 4.45 Zr 7 B 4 amorphous ribbons. A comparative study of the giant magnetoimpedance (GMI) effect and its field sensitivity (g) in the uncoated and Co-coated ribbons is presented. We show that the presence of the Co coating layer enhances both the GMI ratio and g in the Co-coated ribbons. Larger values for GMI ratio and g are achieved in the sample with Co coated on the free ribbon surface. The enhancement of the GMI effect in the Co-coated ribbons originates mainly from the reduction in stray fields due to surface irregularities and the enhanced magnetic flux paths closure. These findings provide good guidance for tailoring GMI in surface-modified soft ferromagnetic ribbons for use in highly sensitive magnetic sensors. The discovery of the so-called giant magnetoimpedance (GMI) effect in soft ferromagnetic ribbons makes them attractive for magnetic sensor applications. 1,2 GMI is a large change in the ac impedance of a ferromagnetic conductor subject to a dc magnetic field. 1 The impedance (Z) of a ferromagnetic ribbon can be calculated by 3 Z ¼ R dc jka cothðjkaÞ;( 1) where a is half of the thickness of the ribbon, R dc is the electrical resistance for a dc current, j ¼ imaginary unit, andThe impedance is related to the skin effect characterized by the skin depth (d m ), which, in a magnetic medium, is given bywhere q is the electrical resistivity, m T is the transverse magnetic permeability, and f is the frequency of the ac current. The application of a dc magnetic field H dc changes m T , and consequently d m and Z. Since GMI is observed at high frequencies (>1 MHz), the skin effect is significant enough to confine the ac current to a sheath close to the surface of the conductor; GMI is therefore a surface-related magnetic phenomenon. 2,3 As such, the surface roughness of a material is important and can considerably reduce the GMI magnitude if the surface irregularities exceed the skin depth. [4][5][6][7] As an example, reducing the surface irregularities of Co-based amorphous ribbons by chemical polishing was found to greatly enhance the GMI effect. 8 Peksoz et al. recently reported that the coating of the Co-based ribbon surface with CuO or a diamagnetic organic thin film improved the GMI effect. 9,10 While the origin of the enhanced GMI effect in the samples 9,10 is not well understood, these investigations open up new opportunities for improving GMI effect in soft ferromagnetic ribbons. We report here a comparative study of the GMI effect and its field sensitivity (g) in Co 84.55 Fe 4.45 Zr 7 B 4 amorphous ribbons with and without 50 nm thick Co layers deposited on either the free ribbon surface (surface roughness, $6 nm) or on the wheel-side ribbon surface (surface roughness, $147 nm). This composition has a high Curie temperature compared to Fe-based amorphous alloys 11 and is responsive to field annealing. 12 We find a large enhancement of th...

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confidence: 99%

Enhanced giant magnetoimpedance effect and field sensitivity in Co-coated soft ferromagnetic amorphous ribbons

Laurita

Chaturvedi

Bauer

et al. 2011

Journal of Applied Physics

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“…We present a tunable sensitivity by changing the strength of the magnetization of the GNPs/YIG composite. There are reports on the surface modification of magnetic ribbons by coating [27,28,30,31,45] have related this phenomenon to the closure of magnetic flux path and reduction of surface roughness. The MI field sensitivity can be defined as η = d(ΔZ/Z(%))/d(H).…”

Section: Sensing Of Gr/yig Compositementioning

confidence: 99%

“…There are reports on the magnetic field sensitivity enhancement by coating layers with different magnetization and conductivities on the surface of MI sensors. [27][28][29][30][31][32] They can tune the MI response mainly due to closure of magnetic flux path at the surface of the MI elements. Interestingly, MI sensing element preserves as a surface media to probe the spin-orbit torque due to non-magnetic Pt [33] and IrMn [34] layer, as the thin skin depth is quite sensitive against tiny changes at the surface.…”

Section: Introductionmentioning

confidence: 99%

Effect of YIG nanoparticle size and clustering in proximity-induced magnetism in graphene/YIG composite probed with magnetoimpedance sensors: Towards improved functionality, sensitivity and proximity detection

Hosseinzadeh

Jamilpanah

Gharehbagh

et al. 2019

Composites Part B: Engineering

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Proximity-induced magnetism (PIM) in graphene (Gr) adjacent to magnetic specimen has raised great fundamental interests. The subject is under debate and yet no application is proposed and granted. In this paper, toward accomplishment of fundamental facts, we first explore the effect of particle size and clustering in the PIM in Gr nanoplates (GNPs)/yttrium iron garnet (YIG) magnetic nanoparticle (MNP) composite. Microscopic analyzes suggest that fine MNPs distributed uniformly on the GNPs have higher saturation magnetization due to the PIM in Gr. We propose that such magnetic plates can thus be used to shield the stray field generated on the surface of magnetic sensors and play a role as a magnetic lens to prevent the field emanating outside the body of magnetic specimen. The GNPs/YIG composites are coated on a magnetic ribbon and proposed for application in magneto-impedance (MI) sensors. We show that such planar magnetic flakes enhance the MI response against the external applied magnetic field significantly. The suggested application can be furthermore developed toward bio-sensing and magnetic shielding in different magnetic sensors and devices.

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“…Though the detection sensitivity for Dynabeads is lower than that of the previous studies, [21][22][23] the fabrication process of the ribbon-based GMI sensor is simpler. The enhancement of the GMI effect in the Co-based amorphous ribbons can be achieved by coating with copper, zinc oxide, diamagnetic organic thin lms, cobalt, or carbon nanotubes, [32][33][34][35][36] applying tensile stress, 37 an annealing treatment 38 and appropriate geometries. 28 So in theory the detection limit for Dynabead detection could be improved by using a highly sensitive ribbon GMI biosensor.…”

Section: Detection Of Magnetic Dynabeadsmentioning

confidence: 99%

A GMI biochip platform based on Co-based amorphous ribbon for the detection of magnetic Dynabeads

et al. 2015

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Giant magneto-impedance effect in diamagnetic organic thin film coated amorphous ribbons

Cited by 28 publications

References 13 publications

Enhanced giant magnetoimpedance effect and field sensitivity in Co-coated soft ferromagnetic amorphous ribbons

Enhanced giant magnetoimpedance effect and field sensitivity in Co-coated soft ferromagnetic amorphous ribbons

Effect of YIG nanoparticle size and clustering in proximity-induced magnetism in graphene/YIG composite probed with magnetoimpedance sensors: Towards improved functionality, sensitivity and proximity detection

A GMI biochip platform based on Co-based amorphous ribbon for the detection of magnetic Dynabeads

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