High-sensitive giant magnetoresistance in permalloy/Cu multilayers

We report on giant magnetoresistance (GMR) of Si(100)/Cu-20nm/(Py-d(Py)/Cu-d(Cu))(100) where Py=Ni83Fe17, multilayer films prepared by face-to-face sputtering with 0.5 less than or equal to d(Cu)less than or equal to 3.5 nm and 0.5 less than or equal to d(Py)less than or equal to 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 J(AF) The highest GMR sensitivity (0.5%/Oe) has been achieved for d(Cu)=2.1 nm and d(Py)=3.5 nm.