GIANT MAGNETORESISTANCE EFFECT AND ELECTRIC CONDUCTION IN AMORPHOUS-COFEB CU/CO SANDWICHES/

Giant magnetoresistance (MR) effects have been investigated for spin v alve sandwiches using amorphous(a)-(Co0.9Fe0.1)(80)B-20 alloy layers. In an a-CoFeB/Cu/Co sandwich, a MR ratio as large as 6% was obtained, and a MR curve was found to saturate in a field within 100 Oe. The res istivity is 40-60 mu Omega cm. In a CoFeB(4 nm)/Cu(2 nm)/a-CoFeB(2 nm) /NiO(10 nm) sandwich, MR ratios as large as 4% were also obtained. The maximum held sensitivity of the sandwich is about 2.5%/0e. (C) 1996 A merican Institute of Physics.