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 excha nge-biased spin valve, Nb/FeMn/Py (pinned)/Cu/Py (free)/Nb, is shown to enh ance A Delta R, the difference in specific resistance between the states wh ere the magnetizations of the two Py layers are parallel and antiparallel t o 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 resistanc e contacts can enhance A Delta R, the numerator of the magnetoresistance. ( C) 2000 American Institute of Physics. [S0021-8979(00)57308-3].