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Magnetoresistance Magnetometry of (Ni80Fe20)1-xIrx Wires with Varying Anisotropic Magnetoresistance Ratio



C A. Vaz, E Blackburn, M Klaui, J A. Bland, L Gan, William F. Egelhoff Jr., E Cambril, G Faini, W Wernsdorfer


We report room and low temperature magnetoresistance measurements on sub-micrometer scale elements (wires and crosses, 1.0, 0.5 and 0.1 m) of (Ni80Fe20)1-xIrx (x approximately equal} 2 %) with varying Ir concentrations. For the particular Ir concentrations studied, the anisotropic magnetoresistance(AMR) ratio varied between -0.043% and -0.035% at room temperature. For thesingle wires (0.5- 1 υm) the MR versus eld characteristic is similar to that reported for (Ni80Fe20) wires of similar size, but an opposite sign of the AMR is observed for x > 2 %. For H parallel to the wire axis, the reversal is determined by the sweeping of a few domains which give rise to 'ears' in the MR-Hcharacteristic. For H perpendicular to the wire, a parabolic variation is seen corresponding torotation of the magnetisation, but a negative slope in the MR-H characteristic is obtained at high fields as in permalloy wires. This suggests that the high field behaviour originates from a distinctly different mechanism (e.g., surface scattering) from that of AMR.
Journal of Applied Physics
No. 10


domains, Ir alloy, magnetoresistance, permalloy, surface scattering


Vaz, C. , Blackburn, E. , Klaui, M. , Bland, J. , Gan, L. , Egelhoff Jr., W. , Cambril, E. , Faini, G. and Wernsdorfer, W. (2003), Magnetoresistance Magnetometry of (Ni<sub>80</sub>Fe<sub>20</sub>)<sub>1-x</sub>Ir<sub>x</sub> Wires with Varying Anisotropic Magnetoresistance Ratio, Journal of Applied Physics (Accessed April 18, 2024)
Created April 30, 2003, Updated October 12, 2021