STRESS-INDUCED ASYMMETRIC MAGNETOIMPEDANCE EFFECT IN Ni₈₀Fe₂₀/Cu COMPOSITE WIRES

The magnetoimpedance effect of Ni₈₀Fe₂₀/Cu composited wires was experimentally investigated by varying the Ni₈₀Fe₂₀ coating thickness. An asymmetric MI behavior with a tunable linear region around zero magnetic field by altering the thickness of Ni₈₀Fe₂₀ layer was demonstrated. And the MI behavior was governed by the different anisotropy induced by the residual local stress in the multi-layer region. In addition, our investigation also suggested that the interactions between interface phase and outer phase of coating layer decreased with thickness, resulting in the domination of the asymmetric MI characteristic. For thickness of 485 nm, the sensitivity was up to 225%/Oe from -2 Oe to 2 Oe, providing a promising candidate for linear sensor application.