Dependence of exchange coupling on antiferromagnetic layer thickness in NiFe/CoO bilayers

A systematic study of the dependence of exchange coupling in NiFe/CoO bilayers on CoO layer thickness tAF from 5 to 500 Å has been made. For large CoO thicknesses (tAF>100 Å), the exchange field varies as 1/tAF, whereas for small CoO thicknesses (tAF<100 Å), finite-size scaling of the Néel temperature TN and also the blocking temperature TB dominate.