Magnetoresistance of antiferromagnet CoFe/Ru/CoFe/IrMn top spin valve with thermal stability

Abstract

Thermal stability and magnetoresistive properties of synthetic antiferromagnet spin valves (SAF/SV) having the Ta20/NiFe20/CoFe20/Cu22/CoFe25/Ru5/CoFe22/IrMn40/Ta20 (in Angstrom) structure were investigated. The SAF/SV annealed for a 1 h at 200degreesC exhibits a magnetoresistance (MR) ratio of 8.8%, an effective exchange coupling field (H-eex) of 1170 Oe, and an antiferromagnetic (AF) saturation field (H-s) of 5200 Oe at room temperature. H-eex varies in approximately a 1/t(AP2) (t(AP2) is the thickness of CoFe layer adjacent to antiferromagnet layer). H-eex and MR ratio are stabilized after the first annealing cycle, and it is thought that this SAF/SV reveals higher thermal stability. (C) 2004 Elsevier B.V. All rights reserved.