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Journal of Sensors
Volume 2017, Article ID 4365682, 9 pages
Research Article

Magnetoimpedance Effect in CoFeMoSiB As-Quenched and Surface Modified Amorphous Ribbons in the Presence of Igon Oxide Nanoparticles of Water-Based Ferrofluid

1University of Birjand, Birjand 97175-615, Iran
2Ural Federal University, Ekaterinburg 620083, Russia
3Institute of Electrophysics UD RAS, Ekaterinburg 620016, Russia
4University of the Basque Country (UPV/EHU), 48940 Leioa, Spain

Correspondence should be addressed to Galina V. Kurlyandskaya;

Received 19 June 2017; Accepted 12 September 2017; Published 16 October 2017

Academic Editor: Andrea Cusano

Copyright © 2017 Zahra Lotfollahi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Giant magnetoimpedance (GMI) has been proposed as a powerful technique for biosensing. In GMI biosensors based on the magnetic label detection the change of the impedance of sensitive element under the application of an external magnetic field was analyzed in the presence of magnetic nanoparticles in a test solution. Amorphous ribbon-based GMI biodetectors have an advantage of low operation frequency and low cost. In this work, magnetic and GMI properties of amorphous Co68.6Fe3.9Mo3.0Si12.0B12.5 ribbons were studied in as-quenched and surface modified states both without and in the presence of maghemite ferrofluid. After the surface modification the coercivity was slightly increased and saturation magnetization decreased in good agreement with increase of the surface roughness, a decrease of magnetic elements concentrations in the surface layer, and formation of a surface protective oxide layer. The GMI difference for as-quenched ribbons in absence and in the presence of ferrofluid was measurable for the frequency range of 2 to 10 MHz and the current intensities of 1 to 20 mA. Although the proposed surface modification by the ultrasound treatment did not improve the sensitivity limit for ferrofluid detection, it did not decrease it either.