Characterization of exchange coupling at NiFe-CoPt interface

NiFe/CoPt bilayer films were deposited onto Si wafers and the exchange coupling at the NiFe-CoPt interface was quantified by measuring the magnetization curve of the soft layer. By using CoPt layers of different thicknesses, different sputter etching times between CoPt and NiFe deposition steps and different annealing times of the bilayer, the exchange coupling field at the NiFe-CoPt interface was successfully altered. The preliminary data reported here might be seen as an initial step toward controlling and optimizing the interfacial exchange field that provides longitudinal bias for magnetoresistive heads with overlaid structures.