Trilayers and multilayers containing ferromagnetic 80Ni-Fe,Co layers separated by nonmagnetic Cu layers were fabricated using the magnetron sputtering method. For 80Ni-Fe(60 Å)/Cu(dCu)/Co(60 Å) trilayer films, the MR ratio and the exchange coupling strength oscillated with increasing dCu. For 80Ni-Fe(60 Å)/Cu(dCu)/Co(60 Å)/Cu(dCu)/80Ni-Fe(60 Å) multilayer films, however, the exchange coupling between the bottom 80Ni-Fe and the Co layers oscillated, while that between the Co and the top 80Ni-Fe layers decreased monotonously with increasing dCu. Consequently, antiferromagnetic exchange coupling was not achieved between the Co(60 Å) and the top magnetic layer. The reason for the nonexistence of antiferromagnetic exchange coupling is discussed by taking into account the rougher surface of the Co(60 Å) layer caused by the growth of the different crystalline structures.
- Exchange coupling energy
- Giant magnetoresistance