Interfacial roughness effects on interlayer coupling in spin valves grown on different seed layers

We have studied the behavior of interlayer coupling in giant magnetoresista nce spin valves as a function of seed layer composition and spacer layer th ickness. Using in situ scanning tunneling microscopy, we have measured dire ctly the roughness of the top surface of the lower ferromagnetic layer. We find that the seed layer composition is correlated to the roughnesses of th e interfaces inside the spin valve. Interlayer coupling increases with decr easing Cu spacer layer thickness and with increasing interfacial roughness. Results favorably compare to a topographically derived magnetostatic inter action as described by a modified version of Neel's "orange peel" model. (C ) 2000 American Institute of Physics. [S0021-8979(00)05506-7].