Tuning the magnetic exchange coupling at the IrMn/NiFe interface by Cu insertion

The exchange bias effect was investigated in a set of IrMn[100Å]/Cu[tCu]/NiFe[50Å] samples differing for the nominal thickness (tCu) of the Cu spacer layer (tCu = 0, 0.5, 1, 2 Å). The Cu insertion affects the exchange coupling mechanism that, in this system, is ruled by the glassy magnetic behavior of the IrMn spins located at the interface with the NiFe phase. Varying tCu provides a tool to tune the exchange field and the coercivity and their thermal dependence