Mirror Domain Structures Induced by Interlayer Magnetic Wall Coupling

Abstract

We have found that during giant magnetoresistance measurements in $\ensuremath{\sim}10\ifmmode\times\else\texttimes\fi{}10\text{ }{\mathrm{m}\mathrm{m}}^{2}$ $\mathrm{N}\mathrm{i}\mathrm{F}\mathrm{e}/\mathrm{C}\mathrm{u}/\mathrm{C}\mathrm{o}$ continuous film spin-valve structures, the resistance value suddenly drops to its absolute minimum during the NiFe reversal. The results reveal that the alignment of all magnetic domains in the NiFe film follow exactly that of corresponding domains in the Co film for an appropriate applied field strength. This phenomenon is caused by trapping of the NiFe domain walls through the magnetostatic interaction with the Co domain-wall stray fields. Consequently, the interlayer domain-wall coupling induces a mirror domain structure in the magnetic trilayer.