Magnetoimpedance (MI) has been investigated in the as quenched Fe 66-xCoxNi7Si7B20 (x=0, 33 and 66) ribbons. In plane anisotropy was present in as-quenched x=0, 33 and 66 ribbons. The largest MI values for x=0, 33 and 66 ribbons are 25% (at 7 MHz), 26% (at 8 MHz) and 45% (at 8 MHz) respectively. Largest MI values increased with increasing Co due to reduced magnetic anisotropy. Maximum MI values reduced at higher frequencies due to increased anisotropy fields. © 2014 Elsevier B.V.

G. Markandeyulu

Department Of Physics

Ganesh Kotagiri

magnetic anisotropy

Magnetic materials

Nickel

Amorphous magnetic materials

Anisotropy field

Higher frequencies

IN-PLANE ANISOTROPY

MAGNETO-IMPEDANCE

METGLAS

Silicon

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IIT Madras

Physica B: Condensed Matter

Magnetoimpedance (MI) effect was studied on amorphous Co33Fe33Ni7Si7B20 ribbons that were irradiated with N+1, Ar+2 and Xe+5 ions, at energy of 75 keV. The (MI)m [maximum MI in each case] values are 9.4% and 11%, 9.9% and 6.5%, the largest, for the as-quenched and N+1, Ar+2 and Xe+5 ion irradiated ribbons respectively, at 2 MHz. The (MI)m value of the N+1 ion irradiated ribbon was observed to be the highest, due to an induced in-plane transverse magnetic anisotropy. The saturation magnetizations of the ion-irradiated ribbons are not seen to change with respect to that of the as-quenched ribbon; a small increase in the Ms was observed only upon irradiation with Xe5+ ions. The interaction between the large number of domains, with large uniaxial anisotropy led to large (MI)m values, at frequencies above 8 MHz in the Ar+2 ion irradiated ribbon. © 2015 Published by Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Magnetoimpedance studies on ion irradiated Co33Fe33Ni7Si7B20 ribbons

Magnetoimpedance (MI) response of Co66Ni7Si7B20 ribbons treated with artificial urine with protein bovine serum albumin (BSA), artificial urine without protein BSA and healthy male urine was studied as a function of time of incubation. The maximum MI [(MI)m] values of the ribbons treated with artificial urine without protein (RTAU) after 3 h, 6 h, 12 h and 24 h of incubation are 30% (at 4 MHz), 15% (at 5 MHz), 14% (at 10 MHz) and 8% (at 13 MHz) respectively. On the other hand, the respective (MI)m values of the ribbons treated with artificial urine with protein (RTAUP) are 33% (at 4 MHz), 25% (at 5 MHz), 20% (at 8 MHz) and 15% (12 MHz). However (MI)m values of the ribbons treated with healthy male urine (RTHMU) after 4 h, 5 h, 10 h and 15 h of incubation are 71% (at 3 MHz), 57% (at 3 MHz), 25% (at 6 MHz) and 25% (at 5 MHz), respectively. The saturation magnetization (Ms) values of RTAU after 3 h, 6 h, 12 h and 24 h of incubation are 71 emu/g, 65 emu/g, 63 emu/g and 60 emu/g respectively whereas, the respective Ms values of RTAUP are 73 emu/g, 69 emu/g, 67 emu/g and 64 emu/g. The Ms values of RTHMU after 4 h, 5 h, 10 h and 15 h of incubation are 96 emu/g, 90 emu/g, 75 emu/g and 75 emu/g respectively. The decrease in Ms and (MI)m values in RTAU and RTAUP compared to as-quenched ribbon is related to the amounts of various elements etched out from the ribbons and increased surface roughness. The Ms and (MI)m values of RTHMU are seen to have increased after 4 h and 5 h of incubation, due to strain relaxation through removal of strain developed during rapid quenching of the ribbons. On the other hand, the Ms and (MI)m values of RTHMU after 10 h and 15 h have decreased due to deterioration of the surface of the ribbons and thus, increase in magnetic (surface) anisotropy. The decrease in (MI)m and MS of RTAU with the time of incubation are more rapid compared to that of RTAUP, probably due to the larger surface anisotropy due to rapid deterioration of the surface of the RTAU than in RTAUP. Asymmetry in MI profiles of RTAU, RTAUP and RTHMU was observed and is attributed to the non-uniform etching of the surface of the ribbons leading to pinning of the domain wall motion. © 2015, Elsevier B.V. All rights reserved.

Magnetoimpedance studies on urine treated Co66Ni7Si7B20 ribbons

Magnetoimpedance (MI) has been investigated in the laser and microwave annealed Fe66Ni7Si7B20 ribbons. The largest MI [(MI)m] values of the ribbons annealed using laser with energies of 150, 200 and 250 mJ/pulse (mJp) are 25% (at 7 MHz), 30% (at 5 MHz) and 21% (at 7 MHz) respectively. The effect of domain wall pinning on MI was observed as field insensitive regions in the MI profiles in the ribbon annealed using 150 mJp energy. Flower shaped grains in amorphous matrix in the ribbon annealed with 200 mJp energy are responsible for highest (MI)m due to the least anisotropy. In the ribbons annealed for 40, 45 and 50 min at 400 °C using microwaves, (MI)m values are 35% (at 5 MHz), 46% (at 6 MHz) and 29% (at 7 MHz) respectively. The large DC conductivity and the least anisotropy (smallest Hk values) in the ribbon microwave annealed for 45 min at 400 °C resulted in (MI)m reaching its highest value in the ribbons investigated. © 2015 Published by Elsevier B.V.

Magnetoimpedance studies on laser and microwave annealed Fe66Ni7si7B20 ribbons

The magnetoinductance (mi), AC magnetoresistance (ACMR) and magnetoimpedance (MI) in as cast Co68Fe5Nb12B15 ribbons of length from 1 to 5 cm were studied. The mi, ACMR and MI are large for 5 cm long ribbons. At a frequency of 13 MHz, large value of ACMR (67%) compared with the mi and MI is observed. This is explained as due to the decrease of the skin depth with increase of frequency. With the application of the external steady magnetic field the skin depth increases resulting in a large ACMR. The larger values of mi, ACMR and MI ratios for 5 cm long ribbons compared to those in the smaller ribbons may be due to smaller demagnetizing fields. © 2006 Elsevier B.V. All rights reserved.

Large magnetoresistance in magnetoimpedance of Co68Fe5Nb12B15 ribbons

IEEE Transactions on Magnetics

Magnetostriction of Fe-X (X $ =$ Al, Ga, Si, Ge) Intermetallic Alloys

Progress in Materials Science

Giant magnetoimpedance materials: Fundamentals and applications

Biosensors and Bioelectronics

Surface modified amorphous ribbon based magnetoimpedance biosensor

Japanese Journal of Applied Physics

Giant Magnetoimpedance Effect in Co70Fe5Si15B10and Co70Fe5Si15Nb2.2Cu0.8B7Ribbons

Magnetoimpedance studies on as-quenched Fe66-xCo xNi7Si7B20 (x=0, 33 and 66) ribbons

Journal	Data powered by TypesetPhysica B: Condensed Matter
Publisher	Data powered by TypesetElsevier
ISSN	09214526
Open Access	No