Perpendicular-current exchange-biased spin valve structures with micron-size superconducting top contacts

We describe an optical-lithography-based sample preparation technique for measuring the current-perpendicular-to-plane (CPP) magnetoresistance with micron-size current-contact areas on top of magnetic multilayer samples of millimeter in-plane size. We use Permalloy and Co91Fe9 exchange bias spin valves to show that the CPP specific magnetoresistance (area times change in resistance) is independent of the contact area size A over the range 4 μm2⩽A⩽1 mm2.