High-sensitive giant magnetoresistance in permalloy/Cu multilayers

We report on giant magnetoresistance (GMR) of Si(100)/Cu-20nm/(Py-dPy/Cu-dCu)100 where Py=Ni83Fe17, multilayer films prepared by face-to-face sputtering with 0.5 ≤ dCu ≤ 3.5 nm and 0.5 ≤ dPy ≤ 10 nm. It has been shown that the GMR sensitivity depends on the relative changes of resistivity as well as on the value of the antiferromagnetic interlayer exchange coupling strength JAF. The highest GMR sensitivity (0.5%/Oe) has been achieved for dCu=2.1 nm and dPy=3.5 nm