GMR properties of spin-valve structures with Co/Cu-based multilayers

Abstract

We have investigated the magnetoresistance of multilayer structures in the form of a Co/Cu/Co sandwich superimposed on an antiferromagnetically coupled Co/Cu multilayer. The magnetoresistive response consists of two parts. A low-field MR of about 5% that corresponds to the reversal of the top layer in the sandwich, and a high field MR of about 12% with high saturation field typical of a Co/Cu multilayer. The variation of MR response was studied as a function of the Cu thickness in the sandwich structure. In particular, the sample with structure Si/[Co/Cu](5)/Co(25 Angstrom)/Cu(25 Angstrom)/Co(30 Angstrom) exhibits a sensitivity as large as 2%/Oe and a switching field of less than 5 Oe. (C) 1999 Elsevier Science B.V. All rights reserved.