GROWTH OF GIANT MAGNETORESISTANCE SPIN VALVES USING PB AND AU AS SURFACTANTS

We have investigated the use of Pb and Au as surfactants in an attempt to achieve smoother and sharper interfaces in three types of giant ma gnetoresistance (GMR) spin valve multilayers: symmetric spin valves, b ottom spin valves, and top spin valves. The coupling fields are reduce d by a factor of 10 for symmetric and bottom spin valves and by a fact or of 3 for top spin valves, presumably by suppressing roughness and i nterdiffusion at the Co/Cu/Co interfaces, when similar to 1 monolayer of Pb is deposited in the early stages of spin valve growth. The Pb ha s a strong tendency to float out or segregate to the surface during de position of the spin valve leaving the GMR largely unaltered. Au is al most as effective as Pb, however the Au tends to be left behind in the spin valve, and the GMR is reduced slightly. Attempts to use Hg as a surfactant were unsuccessful. The coupling held increased, and the GMR decreased sharply. (C) 1996 American Institute of Physics.