Ferromagnetic Resonance (FMR) Study of 70CoNi/Cu/80NiFe Trilayers and 70CoNi/Cu/80NiFe/Cu/70CoNi Five-Layers

Abstract

Interlayer exchange-coupling strength, J, was studied by measuring the ferromagnetic resonance (FMR) of 70CoNi/ Cu/80NiFe trilayers and 70CoNi/Cu/80NiFe/Cu/70CoNi five-layers prepared on glass substrates by magnetron sputtering. In the trilayers, J oscillated between positive and negative values a function of the spacer Cu layer thickness, and two peaks as in the negative value of J were observed. In the five-layers, on the other hand, two values of J were observed. One of those corresponded to J in the trilayers, while the other was positive and decreased monotonically with increasing the Cu spacer layer thickness. These results are consistent with that for the magnetoresistance.