Exchange bias in FeNi/FeMn/FeNi multilayers

• FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering.
• FeNi/FeMn/FeNi trilayers were subjected to a special cooling procedure.
• The interaction between two exchange bias systems across an AF layer was studied.
• The exchange bias fields depend on cooling configuration of FeNi magnetizations.

FeNi/FeMn/FeNi trilayers were prepared in magnetic field by dc magnetron sputtering. After additional heating they were cooled with parallel or antiparallel alignment of the ferromagnetic layers. A difference in the exchange bias field between the two cooling configurations was found. Moreover, after demagnetizing at 200 °C and cooling in a zero field, the resulting hysteresis loop at room temperature shows clearly the existence of various subloops shifted in opposite directions with respect to the zero magnetic field. The findings show that the bulk magnetic structure of the antiferromagnetic layer plays an important role in the pinning of the uncompensated interfacial moments. During the cooling process, both exchange bias systems together play an important role in the formation of the bulk structure of uncompensated spins, which in turn contributes to the behavior of both systems.