Micromagnetic studies of antiferromagnetism and resistance-field curves in giant magnetoresistive Co/Al/NiFe

Magnetic properties and magnetoresistance of a Co/Al/NiFe giant-magnetoresistance (GMR) spin valve are analyzed by a new micromagnetic simulation model for the strongly interacting soft magnetic materials. The coercivity is less than 10 Oe in an isolated Co or NiFe film. However, in the Co/Al/NiFe GMR structure with a 80 Å interlayer spacing, the coercivity of the Permalloy film increases to 208 Oe; and the remnant magnetization in the Co film even has an opposite sign with that in the NiFe film, which means the two magnetic films coupled anti-ferromagnetically in a zero external magnetic field. The looped resistance-magnetic field (R-H) curve is obtained. The noise during the switching process can be decreased and the linearity of the R-H curve can be improved by an orientation distribution of anisotropy fields for the GMR sample