Current induced noise in CPP spin valves

In this paper, an experimental investigation of current-induced noise in current perpendicular-to-plane spin-valve heads is reported. It is found that the sense current yields excitations of coherent spin waves as well as substantial 1/f-like noise when current exceeds a critical value. The noise is magnetic in nature. The criticality and current directional dependence of the noise excitation clearly show that the spin transfer is the cause. Index Terms--Current perpendicular-to-plane (CPP) spin-valve read heads, spin transfer, 1/f noise.