"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

ANISOTROPY OPTIMIZATION OF GIANT MAGNETOIMPEDANCE SENSORS

P. Ciureanu1,* , G. Rudkowska1, L. Clime1, A. Sklyuyev1, A. Yelon1

Affiliation

  1. École Polytechnique Montréal, Montréal, Québec, H3C 3A7, Canada

Abstract

As-cast melt extracted CoFeSiBNb wires 37.5 mm in average diameter prepared by MXT Inc. of Montréal have a predominantly helical anisotropy due to residual tensile and torsional stresses quenched in during preparation. When a supplementary tensile stress is applied along the wire, its easy axis of magnetization rotates towards the transverse (or circumferential) direction, since the magnetostriction of Co-rich wires is negative. Well defined, high amplitude and steep peaks of the magnetoimpedance are obtained when the magnetoelastic anisotropy of the wire reaches an optimum in magnitude and orientation. This optimum may be obtained by fine tuning the applied stress and can be permanently quenched in the material by current annealing the wire. A 50 to 100 mA DC current was used for this purpose. The circumferential DC magnetic field associated with this current also changes the wire anisotropy. After cooling, the wire quenches-in an optimum anisotropy, which maximizes the GMI effect of the wire. Magnetic field sensors with sensitivities as high as 1 kV/(T mm) and figures of merit of about 16 WT were obtained as a result of this optimization, for wires driven by AC currents of 1 mArms amplitude and 10 MHz frequency..

Keywords

Magnetic field sensors, Giant magnetoimpedance effect, Magnetoelastic anisotropy.

Submitted at: April 14, 2004
Accepted at: June 22, 2004

Citation

P. Ciureanu, G. Rudkowska, L. Clime, A. Sklyuyev, A. Yelon, ANISOTROPY OPTIMIZATION OF GIANT MAGNETOIMPEDANCE SENSORS, Journal of Optoelectronics and Advanced Materials Vol. 6, Iss. 3, pp. 905-910 (2004)