Exchange bias between NiFe and IrMn/Ru superlattices

The letter reports on the exchange bias between NiFe and IrMn/Ru superlattices. Using the exchange bias effect we have demonstrated the presence of exchange coupling in the antiferromagnetic/nonmagnetic superlattice of IrMn/Ru and observed a larger exchange bias in NiFe/[IrMn/Ru]n than that in NiFe/IrMn bilayers. The enhancement in exchange bias should be attributed to the increase in uncompensated magnetization in IrMn/Ru superlattices.