Enhancing current-perpendicular magnetoresistance in Permalloy-based exchange-biased spin valves by increasing spin-memory loss

Inserting a thin (t* = 0.5 or 1 nm) layer of the antiferromagnet FeMn into the "free" Permalloy (Py) layer of a sputtered, current-perpendicular exchange-biased spin valve, Nb/FeMn/Py (pinned)/Cu/Py (free)/Nb, is shown to enhance A Delta R, the difference in specific resistance between the states where the magnetizations of the two Py layers are parallel and antiparallel to each other. Such an increase is taken as evidence that spin-memory loss (spin relaxation) due to the FeMn is strong, and that judicious insertion of a source of spin relaxation into a multilayer with high specific resistance contacts can enhance A Delta R, the numerator of the magnetoresistance. (C) 2000 American Institute of Physics. [S0021-8979(00)57308-3].