Effect of Ru impurities on magnetoresistance in Co/Ru/Co(Ru) sandwiches

摘要

Magnetoresistance (MR) measurements have bene performed on two series of Co (3.2 nm)/Ru (x=0.5 to 3 nm)/Co(3.2 nm) and Co(3.2 nm)/Ru(x)/Co_0.92Ru_0.08(3.2 nm) sandwiches prepared by ultra high vacuum evaporation onto mica substrates. At 300 K, all samples of the first series present giant magnetoresistance (GMR) whereas the samples of the second series, and with the same Ru spacer thickness, show an inverse GMR. This inverse GMR is induced by alloying the second Co layer with 8 at